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2020 Elinor Teague past articles

Elinor past article 2020

December 2020 MG website column
December 2020 MG website column
In December and January most gardeners are occupied with pruning deciduous trees and bushes, but there are two important garden chores that are often overlooked during the busy holiday season.In the winter months, gardeners need to constantly monitor soil moisture levels in different spots their gardens and to be prepared to protect vulnerable frost-tender plants from freeze damage.
Check soil moisture levels in your garden before and after rainstorms. You might be surprised to find that the soil in some areas, like those under evergreen tree canopies, in container plants or next to fences or structures, remains bone dry while the soil other more open areas is damp near the surface.Evergreen tree and bush canopies can prevent rainfall from soaking the roots under the canopies and the foliage on container plants can also block rain.Our rainstorms usually blow in from the northwest or western direction; fences and buildings can block much of the rain from reaching the soil near the eastern or southern sides of structures.  
  Map out the rainfall patterns in your garden and arrange for supplemental irrigation in consistently dry areas.Use a trowel to dig three or four inches into the soil in planting beds and near trees.When the top three to four inches is dry, it’s time to deep irrigate.If your automatic sprinkler or drip emitter system is designed to irrigate by zones, set timers to water drier areas for longer periods of time.Or set up soaker hoses or small oscillating sprinklers to slowly soak the dry areas to a depth of 12 inches which is where most plants’ and trees’ roots lie.  
Lawns are usually planted in open areas that receive more rainfall.Cool-season grasses including fescues and perennial rye and warm-season grasses like bermuda grass are both dormant in winter.They may not need any supplemental irrigation during December and January if rainfall amounts are sufficient.If rainfall is light, adjust automatic timers keeping in mid that warm season grasses generally require 6 to 9 minutes of irrigation (by rainfall or sprinklers) in winter.Cool season grasses need just 8 minutes of irrigation a week in December and 15 minutes weekly in late January when they begin to exit dormancy.
Here in the Central Valley we can see frost on the roofs starting in mid-November until mid-February.Our coldest temperatures of the year often occur in late December when it’s common to experience several nights of hard freezes when temperatures fall below 28 degrees.  
Save a few of your old towels and small blankets to use as freeze-protection coverings for semi-tropical and tropical plants including bougainvillea, canna, citrus and some fern varieties.When temperatures are predicted to fall below freezing or when you can see the stars on a cold winter night, cover your plants and deep irrigate the soil around them; irrigate again after the freeze has passed.Wet soil stays warmer than the frosty air.You can also use burlap, canvas tarps, straw, cardboard and wood and canvas frames including market umbrellas that can be placed over small citrus trees in containers.
Non-breathing plastic can transmit the cold to plant tissues.Remove any coverings during the day to allow light, air and sun to warm and dry the plants
November 2020 Master Gardener website column

November 2020 Master Gardener website column

I’m a little late buying my bulbs this year.Spring-blooming bulbs should be planted before Thanksgiving and bulbs that need pre-chilling, especially tulips, should be purchased in early September to allow for at least 6 weeks to 8 of being stored in the refrigerator before planting.I was shopping online for drought and heat-tolerant sparaxis and brodiaea bulbs that don’t require chilling, but as I discovered a few days ago, most online growers and shippers were completely sold out of all bulbs.Local nurseries and garden centers still have small selections in stock of the traditional daffodils and tulips.Daffodils and narcissus are the best bets for late (unchilled) planting and they do quite well in our Central Valley climate, reblooming every year and naturalizing easily.
Here are a few tips and reminders for helping your bulbs survive and thrive during our long,hot summers and brief warm winters.
Planting depth: There was a report about twenty years ago on research that showed that tulips planted 9 inches deep instead of the traditionally recommended 6 inches deep, rebloomed for several years and held their flowers better during early spring hot spells that are common here in the Central Valley.Soil temperatures remain cooler at deeper levels.  
Planting guides for bulbs recommend planting the bulbs at twice the length of the bulb, so a three-inch tulip bulb is usually planted at a depth of six inches.My own research over the last twenty years confirms that planting all bulbs a little deeper does seem to promote rebloom, more heat-tolerant flowers and overall health and vigor.
Soil conditions: bulbs will produce new bulblets and resist rot if planted in well-draining soil. Our soils here in the Central Valley tend to be heavy clay or sandy that do not drain well naturally. Amending the soil in your planting beds with compost or humus will improve drainage and help prevent rot and encourage the development of new bulblets as well.
Summer irrigation: bulbs will rot in consistently wet soil.Planting guides for bulbs usually recommend lifting and storing bulbs in summer in a cool, dry place.Dry and cool places are hard to find in Central Valley summers.Instead, try to plant your bulbs in spots that will not receive heavy irrigation in summer and leave the bulbs in the ground all year.  
Feeding, deadheading and foliage removal: bulbs should receive three annual feedings of bone meal or a bulb food.Place a tablespoon of bulb food at the bottom of each planting hole in fall, sprinkle another tablespoon of food over the leaf tips as they poke through the soil in early spring and then sprinkle at least a tablespoon of bulb food over every leaf clump after spring flowers have been deadheaded.Wait to remove the leaves until they’ve turned brown.Green leaves continue to send nutrients to the bulb after flowering.
Our warm climate often causes spring-blooming bulbs to set flowers in fall.Feed those bulbs three times a year as well and consider throwing a bucket or two of ice a week in late summer onto the spots where you’ve seen early bloomers.
October 2020


October is a great month to start lawns from seed or to repair, thatch and reseed an existing lawn.It’s also a great month to reconsider having a lawn.Many of us like the look of a green expanse of open space around our homes but lawns need a lot of water and regular feeding and mowing.There is a wide selection of ground covers that can be drought-tolerant and easier-care substitutes for lawn grasses.Here are just a few suggestions that have been successful in my lawnless garden.You’ll notice that all of these are flowering ground covers that, in addition to providing some color during their flowering season, also provide nectar and pollen to attract bees and other pollinators.These spreading and trailing ground covers are not well-suited to areas with foot traffic.


Myoporum prostratum:grows 3 to 6 inches tall and spreads to 9 feet.The many stems are covered with evergreen narrow, long, light-green leaves.Small white flowers in spring are followed by tiny purple berries.Needs little water when established.

Cerastium (also know as Snow in Summer):plants grow as small tufts of silvery-green that are covered with tiny white flowers in early summer.Needs moderate water and some afternoon shade in summer.Plants can be mowed or sheared in winter.Cerastium live only a few years.

Sonoma Coast’ “White Yarrow”, a California native:Very pretty 2-inch tall dark green fern-like leaves slowly spread to densely cover the ground.White umbrella flowers shoot up on three to four-inch stalks in spring and die back in the summer heat.Considered drought-tolerant but has required more water than expected.

Verbena:there are several types of low-growing verbenas.‘Tapien” is very hardy and can be mowed or sheared several times during the long flowering season to encourage rebloom. Needs moderate water and monthly fertilizing from spring through summer.

Pratia (also know as Blue Star Creeper);an old-time ground cover (formerly named Isotoma) that needs rich, well-drained soil and some shade but does tolerate light foot traffic and is almost foolproof when grown in ideal conditions.Tiny light green leaves show off the very pretty tiny blue star-shaped flowers in spring.

Yerba buena, a California native and a member of the mint family:Plants bear evergreen dark green leaves on long stems that spread 2 to 3 feet long.Small white flowers appear in spring.

Considered to be drought-tolerant but needs more water and afternoon side during our long, dry Central Valley summers.

Violets, clover and English daises:some people consider these three ground covers to be ugly weeds when spotted in their lawns, but they are really very adaptable, hardy ground covers.Violets will die out in our extreme summer heat as do English daises, but both reappear in spring.Plant violets and English daisies in more isolated spots in the garden and just let the clover take over the bare spots in your lawn.

September 2020

Due to computer issues we have no September issue. 

August 2020 Master Gardener website column

It’s still too hot to sow seeds directly into the soil but Central Valley gardeners can buy and start seeds for transplants of cool-season crops in August for planting into the garden in six to eight weeks or in late September and early October.  We can also plant seeds of cucumbers and beans now for a second shot at a good crop of these two favorite summer vegetables. 

Cucumbers and beans drop their flowers when temperatures are above 90 degrees.  Because our Central Valley temperatures rarely fall below 90 degrees from May until September, beans of all types and cucumbers usually stop producing new fruit here in mid-May.  Flowerless cucumber vines can often be nursed through the summer and will start to set flowers again in mid-September.  Cucumber seeds can also be sown into garden beds or started in pots as transplants in late August. The fruit of cucumber varieties requiring fewer ‘days to maturity’ (typically 50 to 55 days) will ripen in late October and early November.  Like other cucurbits (melons, squash), most cucumber varieties are pollinated only by bees so make sure that your flowering bee-friendly plants are well-watered, deadheaded and fertilized to continue to attract bees and other pollinators into your garden.  There are some cucumbers that are parthenocarpic or self-pollinating and seedless.  Parthenocarpic cucurbits are a good bet if your garden does not host a large bee population.

Many bean varieties suffer greatly from heat stress; stressed bean plants attract aphids, whiteflies, leafhoppers, mites and other pest insects some of which carry diseases including mosaic virus that will kill the plants.  A fall crop of beans can be sown from seed in mid to late August which allows at least 60 days before the first frost in mid to late November knocks down the vines.

Excessive nitrogen will cause bean plants to fail to set pods.  Fertilize beans monthly with a low-nitrogen granular fertilizer such as a 4-6-2 formulation.  Because tomatoes are also sensitive to high levels of nitrogen in the soil and beans fix nitrogen into the soil, avoid planting tomatoes next year where beans were planted this year.  Bush beans set pods for two to three weeks; pole beans have a longer three to four week flower production period.  Sow a second or third crop of bean seeds every two weeks for an extended harvest.

Seeds for vegetables were in short supply this spring as home gardeners began to grow their own crops to supplement their food sources.  Support our remaining local nurseries by shopping there first for seeds and, later in the growing season, for transplants.  We can sow seeds for leafy greens including spinach, arugula, chards and lettuces in early September if those seeds are labeled “slow to bolt”; they’ll be less likely to set flowers and turn bitter in the fall heat.   Root crops such as carrots, beets, radishes are heat-sensitive.  Wait until early October to sow root vegetable seeds.

Start transplants in August of brassica crops such as broccoli, Brussels sprouts and cabbages for planting into the garden in mid to late October when daytime temperatures will be much cooler. 

July 2020 Master Gardener website column

Plants and trees have strong reactions to both high and low temperature extremes. The signs of cold weather winter dormancy (leaf fall from deciduous plants, slow or stopped growth) are well-known, but not all Central Valley gardeners are aware that the plants and trees in our gardens go into a summertime state of semi-dormancy during July and August, the hottest months of the year here.  This phenomenon is specific to hot, arid climates like ours.


Cool-season lawns (fescue and perennial rye) go fully dormant in summer, producing no new blades so that the lawn grasses thin out and lose some of their green color.  Roses are among the hardiest of perennial flowering bushes but even roses set few new buds in mid-summer and the few flowers that bloom tend to have paper-thin petals and far less fragrance.  Vegetable flowers drop in the heat before they set fruit and many plants seem stunted.

              When temperatures are above 96 degrees, as they are nearly every day in mid-summer here, plants try to conserve energy and reduce transpiration or loss of precious moisture through their leaves by closing up their breathing pores (stoma).  In other planting zones, plants get some relief from the heat at night, but in our extremely dry, hot climate night time temperatures seldom fall below 70 breeze less degrees.  It’s our hot summer nights that stimulate semi-dormancy.  

              When trees, bushes, flowering annuals and vegetables, and lawn grasses are in a state of summertime dormancy, they will still require watering to maintain consistently moist soil, but they will require little or no fertilization.  In fact, fertilizing semi-dormant plants and trees to try to force new growth can actually stress them further.  If plants seem unhealthy, try applying homemade fresh compost to each plant instead of a commercial fertilizer.  Homemade compost contains lower levels of nutrients and higher amounts of beneficial micro-organisms and fungi than commercial foods.  The beneficial micro organisms and fungi attach to plants’ roots and increase the plants’ ability to draw up water and nutrients.  

              We can resume feeding the plants in our gardens as night hours lengthen and night temperatures begin to drop below 70 degrees, usually in the third or fourth week of August.  Although daytime temperatures may remain in the high 90’s with a few late season really hot spells, the cooler, longer nights in late August allow plants to recover from heat stress overnight so that they once again begin to produce new growth and new buds.

              Fertilization during this transition period should be lighter at first.  Feed at half the recommended rate for the first feeding in August and increase rates as temperatures cool.  Because granular-type fertilizers take longer to dissolve and be absorbed by plants’ roots than liquid fertilizers, they remain available to the roots for a longer period of time.  They are a better choice for feeding plants that are coming out of dormancy.  Avoid feeding with high nitrogen fertilizers (above 6 per cent) that will force rapid new green growth.  (Lawn foods are an exception).

Slow and steady new growth is best for our plants in late summer and early fall.   

June 2020 Master Gardener website column

June 2020 Master Gardener website column

We had our first truly hot spell of the late spring/early summer growing season this last week of May.  Even well-irrigated plants will have suffered the effects of high temperatures.  New transplants and seedlings will have been most affected; plants with established roots systems will have shown less severe signs of heat stress or maybe none at all.  

When daytime temperatures suddenly rise above 90 degrees and night temps remain at 60 degrees or above in late spring as is common here in the Central San Joaquin Valley, plants are unable to adjust quickly to the change in temperature.   The sudden onset of intense heat can severely damage or kill vulnerable plants.  Pansies, spring-blooming bulb flowers, peas and sweet peas are very susceptible to high temperatures and die quickly.

Some of the symptoms of heat stress and drought stress are similar (wilting leaves, brown tips on leaves), but there are symptoms that are specific to heat stress.

              On hot days, the leaves on many tender-leafed plants will wilt.  If the soil contains adequate moisture, the wilting is temporary and the leaves will recover  overnight.  The leaves on well-watered cucurbits including squashes, melons and cucumbers regularly wilt during the day in summer.  It’s normal for these plants.  In the hot sun, moisture transpires rapidly from their large leaf surfaces but the wilting disappears as temperatures cool in the evening. To avoid overwatering cucurbits, check soil moisture levels before irrigating. 

              Many trees including citrus will drop leaves during hot spells as a means to conserve water in the tree; it’s a survival mechanism.  Leaves make food for trees (and provide precious shade).  That’s why it’s so important to deep irrigate all trees regularly in summer.  A good practice is to deep irrigate trees in summer when the top three to four inches of soil is dry which is generally about once a week or more often during the hottest spells.

              Blossom drop during the first hot spell is common on many vegetables including tomatoes, cucumbers and beans.  Eggplants and peppers tolerate higher heat and hold their flowers better than other vegetables.  Tomatoes, beans and cucumbers will begin to set new flowers and fruit again in late August as nights grow longer and cooler. New leaves on many plants will be smaller after a hot spell and flower petals may be thinner.  Flower fragrance is also adversely affected by high temperatures.

              Bolting or flower set occurs on cool-season crops such as broccoli, chard and spinach in late spring in our climate.  Bolting makes leaves taste bitter. To lengthen the growing time of cool-season crops look for seeds or transplants of varieties that are labeled as ‘slow-to-bolt’,’heat tolerant’ or that have Mediterranean names.   

              To help mitigate damage from heat stress, monitor the weather reports and irrigate before the hot spells arrive.  The soil in container plants dries out extremely quickly in hot weather and the plants will need watering at least once a day.  Consider moving containers into shady spots in the garden when high temperatures are predicted.   

Master Gardener Column #5 May 2020

May 2020 Master Gardener Column # 5

 Mega Drought

According to the US. Drought Monitor (www.droughtmonitor.unl.edu), California and all the Western states have been experiencing a mega drought that has lasted for 20 years, from 2000 until the present.  The most serious drought years were from 2014 until 2017.  It has been fairly obvious to most gardeners and others who regularly check the weather that rainfall amounts have been at or below the annual average for most of the last 20 years.  The website www.fresno.climatemps.com lists the current annual average rainfall amount at for the Fresno/Clovis area at 10. 6 inches, lower than the previous longtime average of 11.6 inches often still quoted. 

 With no idea of when and if the mega drought will end, educating home gardeners in methods of water conservation becomes a primary focus for California Master Gardeners.  Some of the steps involved in the effort to conserve water are hard work.  We all need encouragement to step up. 

Amending our native soils is the first and really the most important step to conserve water.  Well-amended soils can retain irrigation water for much longer than unamended soils while still allowing water to drain properly.  Well-amended soils are also less prone to crusting which interferes with water penetration.  

Changing the water retention capability in our garden soils is not a one time process or even a once a year process.  Even when turning large amounts (at least 40% by volume) of compost or humus into planting beds twice a year it will take several years for soil texture to improve enough to significantly reduce water usage.  Amendments should be evenly mixed into the top 6 to 12 inches of soil in planting beds to help retain moisture in the rooting zone.  Plants grown in well-amended soils will require just as much water per watering, but the intervals between waterings can be spaced farther apart.   

Compost is still decomposing; humus has finished the decomposition process.   Both contain small pieces of dead bacteria, root hairs and fungal threads or hyphae.  These organic materials help bind soil particles together, forming aggregates that allow for small and large pore spaces between particles.  Those spaces provide anchorage for roots, hold nutrients and water, and allow for gas or oxygen exchange.  There’s a lot going on in good soil that we’re just learning about.

Fresh organic compost is the best choice for amending garden soil, but it’s not easy to find unless you make your own.   The beneficial fungi and micro organisms in bagged commercial compost are quickly killed by the high temperatures normal to the Central Valley.  Get to know your amendment supplier.  Adding newly shipped commercial bagged humus, mushroom compost and earthworm castings to the compost pile in late winter can increase the volume needed to heavily amend garden soil before spring planting.

After turning amendments into your soil, avoid heavy traffic that will compact the pore spaces and also avoid frequent tilling that will cut the miniscule fungal threads or hyphae.  Fungal hyphae extend many feet through the soil and attract and hold water molecules.  They have a huge effect on water retention.

Sources:  “The Latest Dirt”, Lecture, California Center for Urban Horticulture, October 15, 2016, UC Davis.

“Keeping Plants Alive under Drought or Water Restrictions”, ANR Publication 8553, October 2015, 

Master Gardener column #4, April 2020

Master Gardener column #4 for April, 2020

This will not be a fun summer for Central Valley gardeners. We’re facing another drought year which will entail serious water conservation measures and hard decisions on what and how much to plant. And, the coronavirus crisis has shut down many garden centers and nurseries, our major sources of transplants and seeds suitable for our climate. Gardeners may have a hard time finding a good selection of healthy plants and “stay-at home” restrictions will curtail gardeners’ ability to go on the hunt for plants and seeds Secondary sources of transplants and seeds are hardware/home improvement stores, supermarkets, food co-ops and farmers’ markets. Online seed companies and growers including Burpee’s, Territorial Seeds, and Annie’s Annuals ship transplants, but their supplies are limited and shipping dates do not always conform to our early season planting schedule. Fortunately, gardeners are always ready to help each other by sharing cuttings and extra transplants and seeds.

In early April, temperatures are still in the 70’s and 80’s and we can dare to put in transplants and seeds with the hope that their roots systems have time to develop before the seedlings and new plantings are severely stressed by hot spells that can arrive in in late April and early May. Our summer planting season ends in mid-May when temperatures are just too high to risk plants’ survival.

Seeds for summer vegetables and flowering annuals will remain viable for two to three years if properly stored in a cool, dry place. Cool, dry places are hard to find in our climate. Like many Central Valley gardeners, I buy some fresh seeds every year but save and store favorites.

This March, while staying at home as much as possible, I’ve started some of last year’s seeds indoors for mini-basils (Windowbox and Spicy Globe) and a favorite tomato (Lynn’s Garnet Mahagony) and have planted stored fava bean seeds with good results. Last year’s bush bean seeds (Max’s File Bush and Roma II) and Astia and Golden Rod zucchini seeds will be planted next week. Last year’s container-sized peas (Little Snap Pea Crunch and Peas-In-a Pot) have produced very well this spring.

When times are tough as they are now, I’d suggest concentrating your efforts on growing food crops, but also suggest adding a few flowering annuals or perennials that will attract pollinators to your vegetable garden. Coreopsis, echinaceas and scabiosa are three good perennial choices; all tolerate our summer heat well and will rebloom throughout the summer and into fall if regularly deadheaded. Zinnias are a good choice as a summer annual.

Keep your kitchen waste or regular compost pile active this summer. With supplies of commercial fertilizers and soil amendments becoming scarce, the fresh organic compost from your own pile will provide nutrients, micro organisms and beneficial fungi for your summer garden. Home-made compost is also one of the best soil amendments. Well-amended soils can retain up to 80 % more water than unamended soils. Dig a half bucket of fresh compost into planting beds for each new transplant and add a cupful of compost monthly as a fertilizer.

Master Gardener column #3, March 2020

March 1, 2020 Master Gardener website column

As promised in last month’s column, here’s a brief overview of the spring through fall fertilization schedule for the Central San Joaquin Valley.

Lawns: cool-season grasses including fescues and perennials rye are fertilized monthly in spring and fall when they are actively growing. Cool-season grasses are dormant in winter and during our hot summers and do not require feeding those months.

Warm-season grasses such as Bermuda grass are fed monthly from March/April until late October when they become dormant.

Both types of grasses should be fed with a high-nitrogen fertilizer. Ammonium sulphate is cheap; specialty lawn foods often contain iron and other minerals including sulphur. Lawn foods with added iron and sulfur can be applied to treat for iron deficiencies on other trees, bushes and plants. They work well to correct yellow leaves on gardenias, for example.


Roses: roses should receive their first feeding of the bloom season when new growth is about ½ inch long. The Fresno County Master Gardeners’ handbook “A Gardeners’ Companion for the San Joaquin Valley” gives Bill Welzenbach’s excellent recipes for a first-feeding of a spring tonic for roses as well as a planting formula. Healthy, virgorous roses can do well with a monthly feeding from February till late September of an all-purpose (15-15-15) fertilizer or the same low-number granular food (such as a 4-6-2 formulation) you use to feed your summer vegetables and flowering annuals. Roses reliably bloom 4 to 6 weeks after fertilization. Good to know when planning a wedding in the backyard.

Azaleas, camellias, hydrangeas and other shade-loving plants: most flowering shade-loving plants are fed monthly from February/March until September. Shade plant fertilizer formulations usually contain additional sulfur (3 to 5 per cent) that helps to lower our high soil pH levels here in the Central Valley. Applying additional sulfur in the form of sulfur granules or soil sulfur with an all-purpose fertilizer replicates the shade plant formulation.

Fruit and nut trees: fruit and nut trees do well with two fertilizations per year-a spring feeding just before fruit set and another feeding after harvest. A mature fruit or nut tree, backyard size, will need a cup or two of a high nitrogen food such as ammonium sulfate or a good quality lawn food per feeding.

Citrus: citrus need three feedings in spring of a high nitrogen fertilizer. The first is given in late February, the second at fruit set and the third in late May. A mature citrus tree requires about 5 pounds of ammonium sulfate divided into three for the three annual feedings.

Mature landscape trees seldom need fertilization. Non-flowering landscape shrubs rarely require fertilization unless they are showing signs of nutrient deficiencies such as yellow leaves with green veining, yellow blotches on leaves, or stunted growth and leaf development.

Composts and humus are important soil amendments. Compost is still decomposing; humus has finished the decomposition process. Fresh composts, mushroom composts and earthworm castings contain large numbers of beneficial micro organisms and fungi that aid plants roots’ in drawing up water and nutrients. Adding humus regularly to planting beds increases water retention and improves soil texture and drainage



Master Gardener column #2, February 2020

What to do in your garden this February

Here in the Central San Joaquin Valley we stop fertilization for trees and  bushes, annual and perennial ornamental plants and lawns in October and resume feeding them after the end of our brief dormancy period, usually in early to mid-February when new growth begins to appear.  Regular, consistent feeding of plants and lawn grasses is crucial to maintaining their health and vigor.  Here is a brief overview of fertilizer types and their use in our gardens.

            You’ll see a very large selection of fertilizer types and formulations on nursery and garden center shelves.  Granular fertilizers break down more slowly in the soil than liquid fertilizers so that nutrients remain available to plants’ roots for a longer time and are delivered at a slower rate. Liquid fertilizers tend to contain higher percentages of nutrients than granular because liquid types leach out of the soil more quickly.  Foliar fertilizers can be used to provide a quick boost of micronutrients to correct nutrient deficiencies, but are not recommended as primary fertilizers.  

Fertilizer labels now list the percentages of the macronutrients nitrogen (N), phosphorus (P), and potassium (K) as well as micronutrients, minerals, microorganisms and beneficial fungi.  It’s important for Central Valley gardeners to check fertilizer labels for two things: the percentage of nitrogen in the product and the presence and percentage of sulfur.

Sufficient plant-available nitrogen is often deficient in California soils.  But that doesn’t mean that we should feed all plants with high nitrogen fertilizers on an increased feeding schedule.  Lawn grasses and fruit and nut trees do require feeding with higher nitrogen fertilizers to replace nitrogen that is removed by mowing (lawn grasses) and crop harvesting.  For most of the plants in our gardens, applying high nitrogen fertilizers (above 10 per cent) to ornamental flowering plants and trees will actually encourage overly vigorous foliage growth at the expense of flower production.  A low-number granular fertilizer (say 4-6-2 which contains 4% nitrogen, 6% phosphorus to encourage flower production and 2% potassium which promotes root development and health) applied on a regular monthly schedule should maintain sufficient levels of macronutrients.  This type of formulation can be used successfully on all sun-loving flowering plants including roses and vegetables.

However, our alkaline water and soil in the Central Valley have higher pH levels than the neutral pH levels that most plants require.  High soil pH levels interfere with roots’ ability to absorb micronutrients such as iron and zinc.  The most common signs of iron and zinc deficiencies include interveinal chlorosis (younger leaves are yellow with green veining).  Lowering soil pH levels is a key step in growing healthy plants here.  Sulfur helps lower soil pH levels so that plants’ roots can draw up iron and other micronutrients.  Shade plant fertilizer formulations (i.e, azalea and camellia fertilizers) and citrus foods usually contain additional sulfur, at least 3 to 5 percent, and they can be applied to correct micronutrient deficiencies on all plants.  Adding sulfur granules to native soil when planting roses and other pH sensitive plants and reapplying it bi-annually also helps lower our high soil pH levels.

Next month’s column will cover our Central Valley fertilization schedule.


ET January 2020
Master Gardener column #1, January 2020

What to do in your garden this January

The weather in January is cold and damp, but there’s a lot to do in our gardens this month.  Pruning and weed control are tops on the list.  Make sure to sharpen your pruning tools and have your weed hoe, trowel, spading fork and a long screwdriver handy before starting to work in the garden.

Try to finish up pruning chores by the end of January when deciduous trees and bushes begin to come out of winter dormancy.  Not all plants will come out of dormancy at the same time.  Many varieties of sycamores and Chinese pistache trees tend to enter dormancy earliest in our climate and show new growth earlier in spring than other trees.  They should be pruned in late December or early January.  Japanese maples and crape myrtles  (depending on variety) can be among the last to lose all their leaves in fall and the last to show new growth in spring.  They can safely be pruned in late January or even early February.  Spring-blooming trees and bushes including dogwoods, deciduous magnolias, bridal wreath spirea (white flowers on arching branches) and yellow-flowered forsythia are pruned right after bloom has finished, later in spring, just before their new leaves appear.  Observation and a little research can help you identify the plants in your garden and their pruning schedule.

In the Central San Joaquin Valley, weed seeds begin to germinate as soon as soil temperatures warm again in mid to late January.  Oxalis (yellow flowers, clover-shaped leaves) and poa annua or annual blue grass (small, dark green tufts of grass with fluffy white seed heads) are common springtime weeds.  Both are prolific seed producers. Control for both entails removing the weed before it sets seed heads.

Oxalis is best controlled by hand pulling the weeds’ roots when the plant is small and the ground is soft.  This is a tedious job.  A spading fork can be used to gently loosen the soil around and under the roots before trying to pull out the entire root.  Use a trowel or a screw driver to dig out small clumps of poa annua. 

Use your wiggle hoe to cut down any other weed seedlings as soon as you spot them-before they can set seed.  A 3 to 4-inch thick layer of mulch, compost or humus applied over bare spots will keep sunlight from reaching weeds seeds and prevent germination .  Develop a regular routine of washing off your rakes, hoes, mowers and gardening shoes after every use to prevent weed seeds from being carried throughout the garden.