By Susanne von Rosenberg, UC Master Gardener of Napa County
This is the time of year when we start to prepare our soil beds for spring planting. Because Napa County has large rural areas and many households keep backyard chickens, many of us have access to free manure. Used properly, manure can be an excellent soil amendment and organic fertilizer, increasing soil fertility and tilth. But how do you make sure that you are using it properly and what concerns should you have?
Animal manures typically contain the poop and urine of animals, as well as bedding material, and often undigested or partially digested food that has passed through the animals' digestive tract. They may also contain feathers or hair. Risks associated with using animal manure include food-borne illness, excess nitrogen “burning” plants, high salt levels, herbicide residues and excess carbon.
To prevent food-borne illness, use only manures from herbivores. Do not use manure from pigs, dogs or cats; they may carry parasites that can infect humans. Even manure from herbivores (including cows, horses, goats, chickens and rabbits) can be contaminated with E. coli, Salmonella and Campylobacter bacteria, and Giardia or Cryptosporidium protozoa.
Many commercially available manures are pasteurized to kill soil-borne pathogens. If you have a source of raw manure, it's best to compost it before using. Your compost pile should reach a temperature of at least 140°F for several weeks, and you need to turn the pile several times to make sure all of the manure has composted.
Another benefit of composting manure is that it stabilizes the nutrients, enabling a long, slow release. Aging manure is not the same as composting it. Aging manure creates conditions that cause pathogens to decrease over time due to changes in moisture, temperature and nutrient availability. But pathogens are not actively killed by aging. Aging keeps them from reproducing, so populations slowly decline.
If you do want to use uncomposted manure in food gardens, then you should turn it into the soil at least 120 days before you plant crops that grow in or near the soil (such as root vegetables, but also plants such as strawberries) and 90 days before you plant trellised crops such as tomatoes or pole beans. Even if you've composted the manure, it's best to wait 90 days after you add it to the soil to plant food crops in that bed.
Of course, you can always use uncomposted manure in flower beds as long as you don't plan to eat the flowers. Be extra careful in washing vegetables from any garden beds containing uncomposted manure. People who are more susceptible to food-borne illness (including pregnant women, small children and people with compromised immune systems) should not eat uncooked vegetables from these areas.
Most manures are relatively low in available nitrogen. As with most organic fertilizers, the nitrogen in manure typically requires bacterial action to make the nitrogen available to plants. Uncomposted chicken manure is an exception. It can contain excess nitrogen (high ammonia levels) that can “burn” plants, causing leaf tips or entire leaves to dry out and die. In extreme cases excess ammonia can kill your plants. Overapplying chemical fertilizer can have the same result. Composting reduces the ammonia content so it will no longer burn plants.
On the other hand, if your manure contains a lot of bedding material, you may end up with too much carbon. The ideal ratio of carbon to nitrogen is about 30 to 1. If your composted manure exceeds this ratio, it may immobilize nitrogen in the soil and deprive nitrogen-loving plants (most annuals) of the nitrogen they need. However, high-carbon composted manure would still make a great mulch.
Finally, manures can be contaminated with herbicides such as those used on lawns, turfgrass, pasture and hay crops. Herbicide residues can remain active for a long time, even after passing through an animal's digestive system and, in some cases, even after manure is composted. These residues can cause poor germination and kill seedlings or cause new leaves to become twisted and malformed. Sensitive plants include most vegetable crops and grapes.
The residues do eventually break down and lose activity over time, particularly as they are exposed to microbes, heat and moisture. If you're getting manure from someone else, ask if the animals are eating hay or pasture treated with herbicides. If you're using manure from your own animals, avoid feeding them hay from herbicide-treated fields and avoid using herbicides on their pasture. If you purchase manure, try to get assurance that it contains no herbicide residue.
Be aware that some manures, especially cow or steer manure, can be high in salts. If you have used cow or steer manure, rotate it with other sources to give the salts a chance to leach out of the soil over time.
Napa Library Talks: First Thursday of each month. Register to get Zoom link. Thursday, February 4: Soil is the Solution: Healing the Earth One Yard at a Time.
Got Garden Questions? Contact our Help Desk. The team is working remotely so please submit your questions through our diagnosis form, sending any photos to mastergardeners@countyofnapa.org or leave a detailed message at 707- 253-4143. A Master Gardener will get back to you by phone or email.
For more information visit http://napamg.ucanr.edu or find us on Facebook or Instagram, UC Master Gardeners of Napa County.
By Susanne von Rosenberg, UC Master Gardener of Napa County
One of the reasons I really enjoy having fruit trees is that they are perennials: they give back a lot for relatively little effort. You can get the same benefits from perennial vegetables.
The most common perennial vegetables for our area are artichokes, asparagus and bunching onions (scallions). Others that are highly suited to our Napa Valley climate are cardoon (a relative of artichokes), tree collards (also known as tree kale or walking stick kale), walking onions (also called Egyptian onions) and nopales (prickly pear cactus pads). Additional options include sunchokes (Jerusalem artichokes), perennial arugula (caution: it self-seeds readily) and miner's lettuce (claytonia). In our climate, miner's lettuce acts like a self-seeding annual, but it is a perennial in areas where it receives sufficient moisture.
In addition, you can “perennialize” regular kale, garlic (for green garlic) and, to some degree, Swiss chard and broccoli. To start treating regular kale as a perennial, simply cut it back to a few inches of stalk when it starts to look tired and it will resprout. You can do the same with broccoli. You won't get another large head, but you will refresh the plant and get more small side shoots.
In my yard, Swiss chard readily self-seeds, so there is always some chard growing wherever I water regularly. If it's not in the way, I let it grow. If you plant garlic and don't harvest the bulb, it will sprout as a cluster of green garlic the following growing season and continue to create bulbs underground. Eventually, as with flower bulbs, you will have to dig it up and divide it. Keep some of the best bulbs and replant some cloves for more green garlic.
Think about the pros and cons when you consider adding perennial vegetables to your garden. The main advantage is that you only plant once, yet you harvest for multiple years. Because the plants stay in place longer, they develop stronger and more extensive root systems. This helps the plants take better advantage of available water and nutrients.
Because you're not replanting every year, you're protecting the soil ecosystem. For busy people, adding one or two perennial vegetables per year can be a way of building a productive vegetable garden without investing a lot of time.
You can also let the plants flower, which supports pollinator insects. Some perennials add beauty to your garden. Sunchokes, which are part of the sunflower family, will grow 8 to 10 feet tall with adequate water and produce numerous small sunflower-like flowers.
However, there are some downsides. First of all, you lose flexibility. You have to carefully consider how big the plants will get and whether they make sense at full size in their proposed location. Good locations for perennial vegetables include areas adjacent to other perennials (including berries, fruit trees and ornamental plantings), at the ends of annual vegetable beds and in groupings with other perennials that have similar water needs.
For many perennial vegetables, it takes longer to get harvestable produce. Also, you may need to keep watering them when the weather is dry. When we have a light rainy season, you'll likely have to keep irrigating.
If you are not rotating vegetables and you are keeping them alive year-round, you may have more pest problems. Control pests as soon as you notice them. If you have gophers, you may find that certain perennial plants, such as artichokes, need to be planted in cages because the roots are just too tasty for gophers to resist.
Finally, because you are continuing to water, you are also likely to continue to get weeds, so you will need to cultivate around the plants or mulch regularly to keep the weeds down. Also make sure to check that you are selecting the right kinds of perennial vegetables for your garden. Many common perennial vegetables, such as watercress, require relatively high amounts of water or need sandy, well-drained soil. Others can become invasive. Do your research or contact the Master Gardener help desk for more information.
There are many other perennial vegetables to try if you're adventurous. On the border between herbs and vegetables are sorrel and lovage, which can be used as salad greens, in soups and as seasonings. Daylily tubers, young shoots, buds and flowers are all edible. The leaves of scorzonera (black salsify) can be harvested and eaten just like lettuce. (If you harvest the edible roots, however, you will kill the plant.) Sweet potato leaves are also edible, as are linden tree leaves. Have fun diversifying your garden!
Napa Library Talks: First Thursday of each month. Register to get Zoom link. Thursday, February 4: Soil is the Solution: Healing the Earth One Yard at a Time.
Got Garden Questions? Contact our Help Desk. The team is working remotely so please submit your questions through our diagnosis form, sending any photos to mastergardeners@countyofnapa.org or leave a detailed message at 707- 253-4143. A Master Gardener will get back to you by phone or email.
For more information visit http://napamg.ucanr.edu or find us on Facebook or Instagram, UC Master Gardeners of Napa County.
By Penny Pawl, UC Master Gardener of Napa County
Someone once asked me if it was possible to grow a camellia from seed. Yes, it is possible, but seldom will it have the same flowers as the parent.
A neighbor of mine had a wonderful camellia with a beautiful flower. He kept taking the seeds and sprouting them. I have four bushes from these sprouts, and they are happy and healthy, but the flowers are plain. I call them “my Watsons” after my neighbor.
Many years ago, on a trip to the East Coast, I went to Charleston to see the oldest camellia plantation and the oldest camellia in the United States. Camellias arrived in Charleston in 1786. When I visited, the plant had seed pods on it and somehow one of the pods jumped into my pocket. I planted the seeds and one plant grew. It has since become a beautiful bonsai. But does it bloom? While pruning, I once saw evidence of a couple of blooms but never saw an actual flower. And I would expect any flowers to be plain.
The camellias available in nurseries are hybrids. The number of named camellias is around 20,000. The International Camellia Society published a registry of names, a project that required more than 30 years of research. I did not know that the tea plant (Camellia sinensis), which provides the leaves that people around the world brew daily, is a member of this family.
The most common species, Camellia japonica, was imported to England in the early 1700s and grown in a greenhouse. Our garden camellias belong to this species. Over time, these plants have been hybridized to produce a wide variety of blooms. Hybrids can only be reproduced by cuttings, not by seed.
Camellia japonica bushes bloom in the late winter and early spring. If you want to choose a camellia based on its flower, that's the time to go shopping. One of the biggest camellia shows is in Sacramento each March.
Once a camellia has finished blooming it needs pruning. You can trim quite severely and not affect next year's bloom. The buds for the following winter's bloom form as the plant produces new growth. If you prune after the buds have formed, you will not have any bloom the following winter.
Once established, camellias are fairly drought tolerant. Some of mine get watered only by rain and that does not seem to hurt the bloom. All of these camellias are over 40 years old and well established. Newer plantings need water year-round until they are established.
When selecting a place in your garden to plant a camellia, choose a location that gets dappled sunlight or shade. Plant the camellia a bit higher than the surrounding soil so that any excess water will flow away from the trunk.
Fallen camellia blossoms lying on the ground beneath the bush can cause a fungal disease called camellia flower blight. The disease causes the blooms to have brown petals that fall off. Pick up dead flowers under your bush to foil this disease. Most of the other diseases that plague camellias occur in damp, humid climates and are rarely a problem in Napa Valley.
Napa Library Talks: First Thursday of each month. Register to get Zoom link. Thursday, January 7: Bare Root Basics.
Free Rose Pruning and Winter Care Workshop: Saturday, January 9. Register for the Zoom link.
Got Garden Questions? Contact our Help Desk. The team is working remotely so please submit your questions through our diagnosis form, sending any photos to mastergardeners@countyofnapa.org or leave a detailed message at 707- 253-4143. A Master Gardener will get back to you by phone or email.
For more information visit http://napamg.ucanr.edu or find us on Facebook or Instagram, UC Master Gardeners of Napa County.
By Cindy Watter, UC Master Gardener of Napa County
After the sedate revelry of our pandemic purgatory (and a happy new year to us all), it is time to get back to work in the garden. We have had a few rains, and now would be a good time to prune our roses and tidy up their areas, to help them look their best next spring and summer.
I once taught a rose pruning workshop in Yountville and made two terrible mistakes. The first, and worst, was being frivolous when someone asked what would happen if she didn't prune her roses. I joked that she could end up in a place that was uncomfortably warm. That was wrong. Actually, depending on the roses, and how long you go between prunings, the answers are: a) nothing; and b) something.
You can go for five years without pruning a Cecile Brunner (a climbing polyantha which has many clusters of small flowers), and it will put forth its fluffy pink blooms same as ever. However, if you prune it just a bit after it blooms, you will get a more abundant repeat bloom during the summer.
On the other hand, a rose that is intended for cutting for vases or bouquets will produce larger blooms with sturdier stems if you prune it. These bushes are generally hybrid teas, grandifloras or floribundas, such as Double Delight or Julia Child. Hybrid teas were developed to have stronger stems than the original tea roses from Asia. Grandifloras (large flowers) and floribundas (many flowers on one stem) need strong stems to support all those petals.
The second mistake I made, and it was mortifying, was neglecting to sharpen my clippers before the workshop. Their dull edges would not penetrate the branches of a gnarled, twenty-years-neglected-and-completely-tangled rose, at least in my arthritic fingers. A nice man in the audience helped me out. It was probably a better learning experience that way, but still, sharpen your tools.
Another reason to prune is to remove branches with leaves that have mildew, fungus or rust. First, clean up the area around your roses and remove fallen rose leaves. This will keep winter rains from driving pathogens into the soil and is one of the most important things you can do for general garden health, because it lessens the chances of having to use fungicides later. Do not put these leaves in your home compost, which does not get hot enough to kill the pathogens. Of course you should wear gardening gloves while doing this work.
There are a couple of ways to approach pruning, depending on the purpose of your rose. If you want larger roses with sturdy stems for vase display, prune more aggressively. If you planted roses for landscaping, prune for shape. There are some common guidelines to follow, however.
Remove any damaged or cracked canes. Remove any canes that are thinner than a pencil. If canes are crossing, remove one.
Make clean cuts on a slant. (You sharpened your clippers, right?) All cuts should be above a bud. These cuts will heal so you don't need to paint anything on them. Make sure the center of the plant is open for good air circulation, with no crowding canes. You want to have a shape rather like a vase or an urn.
In general, prune back two-thirds of the growth. Some gardeners take it down even farther.
Roses grow well in Napa County. Even if, to your eyes, the newly shorn rose looks naked, relax. It will grow back better than ever.
Climbing roses shouldn't be pruned the first three years or so after planting. After that, remove all broken canes, leaving about six canes that you will trellis or tie to a form. Every year leave a few new canes and you will have a healthy climbing rose.
Many people are afraid they will destroy their roses if they prune them. Indeed, it is initially a shock to chop off what appear to be perfectly viable leaves and canes. I felt like a horticultural ogre the first time I did it. However, the wonderful thing about plants is that they renew themselves. Roses require a bit more care than our native plants and perennials, but they reward us with their stunning blooms.
Napa Library Talks: First Thursday of each month. Register to get Zoom link. Thursday, January 7: Bare Root Basics.
Free Rose Pruning and Winter Care Workshop: Saturday, January 9. Register for the Zoom link.
Find UC ANR's Healthy Roses publication here.
Garden Questions? Contact our Help Desk. The team is working remotely so please submit your questions through our diagnosis form, sending any photos to mastergardeners@countyofnapa.org or leave a detailed message at 707- 253-4143. A Master Gardener will get back to you by phone or email.
For more information visit http://napamg.ucanr.edu or find us on Facebook or Instagram, UC Master Gardeners of Napa County.
By Susanne von Rosenberg, UC Master Gardener of Napa County
One of the joys of summer is being able to harvest fresh, perfectly ripened fruit from your own garden. December and January are the best months to plant bare-root fruit trees and berries so you can enjoy the bounty in summers to come.
Unlike fruit trees, most berries provide a quick return on your efforts. Strawberries bear fruit the same year you plant them, and blackberries and raspberries produce the year after you plant them. Blueberries are more complicated to grow (they need acidic soil to thrive), but also usually start to produce some fruit in the second year.
Berry plants are less expensive than fruit trees, and if you choose the right kinds, you can expand your berry patch over time. The main drawback to berries is that they all have relatively high water needs.
Brambleberry is another name for blackberries and raspberries. Boysenberries, marionberries and ollalieberries are all varieties of blackberries. Blackberries are well suited to our Napa Valley climate. (In fact, boysenberries were developed here.) Raspberries also do well in all but our hottest areas.
While it's easy to get blackberry and raspberry seedlings from friends (many brambleberries produce suckers from their roots), it's best to start with certified disease-free nursery stock. You can always expand your berry patch by planting some of the suckers. Blackberries and black and purple raspberries also tip-root. If the tip of a cane touches moist ground, it will grow roots from that tip.
To produce well, brambleberries should be planted in full sun. In hotter areas, raspberries benefit from some afternoon shade. Care of brambleberries is fairly simple. Fertilize them once a year at the start of the growing season and keep the soil moist, not soggy, throughout the growing season. The berries also need pruning each year.
Blackberries yield fruit on canes that grew the previous year. The canes growing in the current year are called primocanes. Nurseries sell both erect and trailing varieties of blackberries; trailing varieties need a trellis. Erect varieties have sturdier canes, but the canes will still tip over when they get long, so these varieties also benefit from a trellis. Install trellises when plants are small to minimize root damage.
Most blackberry varieties have thorns, but there are thornless types. I used to be suspicious of thornless varieties, assuming that I would have to sacrifice flavor or vigor for convenience. A couple of years ago, I finally tried a thornless variety, Triple Crown. I was happily surprised by the great flavor and vigor, both of which compare favorably with the boysenberries I have been growing for a long time. To extend your harvest, choose blackberry varieties with different ripening periods.
Raspberries come in four colors: red, yellow, purple and black. The cultivation process for yellow and red raspberries is the same. Red raspberry varieties come in two types: summer bearing and fall bearing. Summer-bearing raspberries produce canes that grow one year, then primarily bear fruit the following year. Summer bearers produce some fruit on the tips of the current season's canes, but a larger crop is produced on one-year-old canes.
Fall-bearing raspberries do the opposite: they bear large crops on the top parts of the current season's canes in late summer and fall. If left to overwinter, canes bear a second crop in the spring, on the lower portions of the canes that fruited the previous year.
My new favorite red raspberry variety is Nova. It is vigorous, has great flavor and has consistently been the earliest and latest producer in my raspberry patch.
Black raspberries (you may have heard them called black caps when you were growing up) and purple raspberries grow on arched or trailing canes. Black and purple raspberries only sprout new canes from the crown (the base of existing canes) or through tip-rooting. Fruit grows on laterals coming from the main canes, so they are pruned differently from blackberries and red raspberries.
To keep your berry patch fruitful, prune out the old (non-fruiting) canes and excess canes. Remove fruiting canes of blackberries and summer-bearing raspberries after they are done fruiting. Then tie up the primocanes.
For trailing varieties, cut the new canes to 8 to 10 feet and loop them around the trellis wires. Fall-bearing raspberries can either be cut to the ground after the fall crop, or you can cut off the top portions of the canes that fruited and get a small spring crop on the lower parts of the canes.
Prune black and purple raspberries to a height of 24 to 30 inches after fruiting. In early spring, cut back any laterals that sprouted to 8 to 10 inches. During the dormant season remove all dead, damaged, weak and diseased canes from all brambleberries. Remove all but 4 to 5 of the most vigorous canes from the crowns of black and purple raspberries and 8 to 10 canes for blackberries. Aim for 4 to 5 strong canes per foot for red raspberries. With the right care through the year, your berries should provide a bountiful harvest.
Napa Library Talks: First Thursday of each month. Register to get Zoom link. Thursday, January 7: Bare Root Basics.
Free Rose Pruning and Winter Care Workshop: Saturday, January 9. Register for the Zoom link.
Got Garden Questions? Contact our Help Desk. The team is working remotely so please submit your questions through our diagnosis form, sending any photos to mastergardeners@countyofnapa.org or leave a detailed message at 707- 253-4143. A Master Gardener will get back to you by phone or email. For more information visit http://napamg.ucanr.edu or find us on Facebook or Instagram, UC Master Gardeners of Napa County.
