The plant family Asteraceae contains over 32,000 distinct species of flowering plants that sport the traits known best as herbal: edible (or toxic) parts, aromatic leaves and flowers, and historical culinary, medicinal, and ornamental use with economic value derived from its uses. Within the family Asteraceae, we find the genus Artemisia one of the most unique, in that the aromatic nature of the plants is vibrant to say the least. Currently undergoing reclassification, this broad genus has between 200 and 400 species with varying levels of these aforementioned traits. Let's take a look at this group.
Members of this genus are typically perennial plants with multiple small yellow or greenish-yellow flower heads grouped into clusters. Leaves vary in color from green to gray-green to silver, usually divided and positioned alternately on the stem. Most are aromatic as essential oils are present and easily released. Their placement in the landscape often allows for smooth transition between intense colors or creates contrast from more dominant green plants.
Commonly named plants found within the genus Artemisia include Mugwort, Sagebrush, Sagewort, Southernwood, Tarragon, and Wormwood. Each of these common names comes with adjectives to specifically differentiate them from other plants similarly named but not in the genus Artemisia. It is important to be aware of a plant's true identity and the cautions necessary when touching and using them. The following represents ten of our favorites that we have encountered over the years.
Common Mugwort = Artemisia vulgaris: Why is it that Latin names are so vivid? Vulgaris certainly sounds awful coming out of one's mouth, so you would imagine this Artemisia would taste awful! You won't be disappointed—it is vulgar! Would you be surprised to know that this Artemisia has ornamental and medicinal value? (Cue Mary Poppins “Just a spoonful of sugar helps the medicine go down….”). Acupuncture practice incorporates burning it to make “moxa” (Mugwort burning) done over key points to stimulate the flow of Qi (pronounced chee), strengthen (thicken) the blood, and promote general health. Various Asian cultures also use it as a dream inducer.
Western Mugwort = Artemisia ludoviciana: This Mugwort is also known as White Sage (sagebrush), a handsome plant with soft, whitish leaves. It is an herbaceous perennial native to central and western United States and Canada in all temperature zones. It has a robust sage fragrance, hence the common name.
White Mugwort = Artemisia lactiflora: Lactiflora is also vividly descriptive, as the flowers of this species are milk white! This plant has silvery green foliage which enhances its ornamental use. The flowers are showy, bearing a resemblance to Astilbe (False Goat's Beard), and attract beneficial insects.
Big Sagebrush = Artemisia tridentata: Not to be confused with a trifecta and in no way related to “Trident” gum (which is cinnamon flavored), Tridentata is a very hardy species that tolerates arid environs. It plays a crucial role in its native Great Basin, surviving on minimal water while providing both food and shelter for members of the community. Utah State University researchers have found that this sagebrush has medicinal properties as a menstrual stimulant and avermifuge (expelling parasites from the body). The leaves are silvery green.
California Sagebrush = Artemisia californica: Grow this shrub in native plant gardens or use as a drought-resistant landscaping choice. Its silvery foliage exemplifies the Atremisia genus. California sagebrush is sometimes confused for a true sage (Salvia) due to its common name and leaves that smell like sage. It is a crucial part of the coastal sage scrub habitat.
Prairie Sagewort = Artemisia frigida: Also known as Prairie Sagebrush or Fringed Sage (sagebrush), this low-growing woody sub-shrub native to the Black Hills of South Dakota and Wyoming has silvery, frilled leaves that are very aromatic. Various Native American tribes identify this plant as one of their smudge plants.
Sagewort = Artemisia annua: This Artemisia is more commonly known as Sweet Annie or Sweet Wormwood, but is also known as Qing-hoa or Qing-guo. Different from most other members of this genus, it is an annual grown from seed as a late-flowering cultivar. Its cultivation in China began over two thousand years ago. The aromatic foliage is pervasive and pleasant. It contains a prominent level of Artemisinin, a drug incorporated into ACTs (Artemisinin-based Combination Therapies), which are the current treatment for malaria caused by Plasmodium falciparum as well as malaria due to other species of Plasmodium. Scientist Tu Youyou discovered this in 1972, resulting in a shared Nobel Prize in Physiology/Medicine awarded in 2015! Additionally, the aromatic branches placed in dried floral arrangements and scented wreaths really add flair to the handicraft.
Southernwood = Artemisia abrotanum: This woody shrub is native to the Mediterranean and is also very aromatic. It is lemon-scented and works very well as a moth repellent. It also makes a bitter tonic! Bitters add flair to foods in cooking applications and a punch to most dry liquors.
Tarragon = Artemisia dracunculus: French Tarragon is this actual species. While French Tarragon is the most popular culinary Artemisia in the world, people in fact grow more Russian Tarragon (A. dracunculoides) world-wide due in part to its adaptability. Both are green leaved and have a healthy anise flavor and aroma. French Tarragon is a little more difficult to keep happy in a garden due to its want for the perfect Mediterranean climate. But if you can create French Tarragon's happy place, you will not be disappointed. While other plants also have anise flavors, these two Artemisia are the bomb amongst Michelin-grade chefs!
Wormwood = Artemisia absinthium: You knew I wouldn't leave this one out! Absinthe was once the alcoholic spirit of choice in Europe, an anise-flavored spirit derived from the flowers and leaves of Artemisia absinthium, together with green anise, sweet fennel, and other culinary and medicinal herbs. The concern one should have with pure, untreated Wormwood is the chemical contained in its essential oil, Thujone. Research regarding this chemical confirms it to be a toxic ketone that can cause hallucinations and seizures. Warning! Danger Will Robinson! Danger! Don't get “Lost in Space.”
What an exciting group of plants! I hope you enjoyed the brief introduction.
For more information on Artemisia, click here.
- Author: Lee Miller, UCCE Master Gardener
The Fourth of July is a time of patriotic celebration and is also a target date for starting transplants for a cool season vegetable garden. It is an unusual time of year to be thinking cool, yet the summer solstice is past, days are getting shorter and fall approaches though many hot days lie ahead. I start my seedlings in wooden flats filled with compost in which I seed cabbage, broccoli, cauliflower and Brussels sprouts. Recently, I have given up on the Brussels sprouts as they tend not to do well here. These winter veggies can be transplanted to the garden in late August-early September. Keep the flats watered and thin or transplant to other flats if the seedlings are too crowded.
Onion seeds can be started in a flat, about the 20th of August. Beets, kale, kohlrabi, carrots, chard, turnips, parsnips and lettuce can be directly seeded into the garden near the end of August. Sometimes using flats to start lettuce is a good defense against snail or slug attacks on vulnerable small lettuce seedlings that can happen when directly seeded in the garden.
If not done already, prop up those orchard trees that are weighty with fruit to avoid limbs breaking. July is a time for harvesting Gravenstein apples and other summer apples. In our hot climate, summer apples often soon leave the tree after ripening so pay attention and pick daily. You can refrigerate them for a few days until you have enough to make several batches of apple sauce or jelly.
It is a good time to do some summer pruning of apples and other fruit trees. Summer pruning reduces vigor. It will keep tree size manageable and will improve your crop for this year and next year too. There are videos on YouTube that will show you how to do it see:
Plan to begin harvesting tomatoes, peppers and eggplant. Peppers often sun scald in our hot climate so taking off some of the blossoms early to retard fruit development will encourage the plant to grow more foliage to shade the crop. Corn, zucchini and other summer squash need to be picked frequently. It is not too late to plant some beans, pumpkins, Hubbard squash, butternut squash and corn for fall harvest. Paste tomatoes such as Roma, San Marzano or Amish Paste are excellent canned for those soups, beans and stews next winter, and nothing beats the delicious sweetness of tomato juice canned from home grown tomatoes.
When blackberry harvest is over, it is time to prune out the floricanes and tie or direct the new primacanes in a vertical orientation and head them back at about 6 ft. If you have the trailing type, tie them to the wire horizontally.
If you remember to deadhead perennials such as coreopsis, dianthus, valerian and more blooms will be our reward. Pruning perennials is a complex task, so consult a good book on the subject such as “The Well-Tended Perennial Garden, Planting and Pruning Techniques” by Tracy DiSabato-Aust. This Fine Gardening article is helpful for deadheading perennials. Roses will bloom much more vigorously this fall if you deadhead the spring blooms, but remember to deadhead back to a 5-leaf leaflet just as you would when harvesting.
Dahlias need to be monitored for the appearance of spider mites. Water spray on the foliage to wash off dust and will help keep them in check, but if they persist, a spray of Safer soap or Neem oil will help control them. Thrips are also a problem for dahlias and weekly spraying with an insecticidal soap can help keep them under control. The Western Flower thrips is most likely the pest. They are yellow or brown and very hard to see even as adults as they are 1/20th of an inch long. Spraying daily with water also helps as thrips like dry conditions. Spinosad and Neem oil will also control them.
If you haven't already done it, mulching is in order for peppers, tomatoes, dahlias and landscape plants, to conserve moisture. For the vegetables use compost, for dahlias, use leaves or straw, and for the landscape plants, use wood chips or bark.
For lawns, mow high at 3 inches in July and August during summer heat and keep the blade sharp. If you haven't already adjusted your irrigation controller for hot summer higher irrigation needs, it is time to do so. September is time to dethatch, aerate and fertilize for cool season lawns of fescue or bluegrass.
Mid-September is a good time to sow California poppies and other wild flowers and time to plant annuals for winter color. Perennials such as dianthus, foxglove, coreopsis, geum, penstemon, phlox and yarrow planted in the fall will get their roots down better with winter weather. Or you can transplant to larger pots to let them grow larger before transplanting to the garden. It is also time to order fall bulbs to get top quality ones for fall planting. Plant daffodils for cheerful ones like these next spring! Happy gardening!
Every plant has a sole purpose in its life: it must propagate or become extinct. This interesting horticultural term highlights one of the more extraordinary means of seed dispersal.
Elaiosome, e-lay-o-zome, n. (Greek: elaio = oil + soma = body) meaning ‘oil body'. Some plant seeds have an attached structure that is filled with lipids and proteins. This oily knob attracts ants that carry the seeds back to their colony to feed the babies and adults. When the structure has been cleared the remaining seed is thrown in their garbage heap. This results in the seeds germinating in a rich compost pile away from the parent plant. It is an ingenious seed dispersal mechanism that is symbiotic with maintaining ant colonies and their health.
Research on the phenomenon counts between 11,000 and 23,000 species develop seeds with elaiosomes. This is less than 5% of plant varieties but still extraordinary numbers. Common examples include violets, bleeding hearts, myrtle, castor beans (for making castor oil – ick), hyacinths and trilliums.
As the warm, sun-drenched days of summer arrive, our gardens and landscapes burst into full bloom. However, along with the vibrant growth and beauty come unwelcome visitors that can threaten the health and productivity of our plants. Among the most persistent summer pests are katydids, bindweed, and the troublesome tomato blossom end rot. Understanding how to manage these common problems can help ensure your garden thrives all season long.
In this article, we'll explore practical solutions and tips for keeping these garden invaders at bay, while also debunking common garden myths surrounding blossom end rot.
MANAGING KATYDIDS ON CITRUS
During a recent stroll through my garden, I noticed some critters munching on the leaves of my mandarin orange tree. Upon closer inspection, I identified the culprits as katydids. These insects can pose a significant challenge to citrus growers, causing damage to both leaves and fruit. Fortunately, I found only two katydids on my tree and quickly handpicked and removed them. To help you manage katydid infestations on your citrus trees, here are several effective strategies:
Cultural Controls - Keep the area around citrus trees clean and free of debris where katydids might hide. Regularly prune trees to remove dead or infested branches, which can reduce katydid habitat.
Biological Controls - Encourage natural predators of katydids, such as birds, spiders, and predatory insects, by maintaining a diverse garden ecosystem. Introduce beneficial insects like parasitic wasps that can help control katydid populations.
Physical Controls - For smaller infestations, manually remove katydids from trees.
Chemical Controls - Use insecticidal soaps or neem oil, which are less harmful to beneficial insects and the environment. In severe cases, apply insecticides labeled for use against katydids. Be sure to follow all label instructions and consider the impact on non-target species.
Integrated Pest Management (IPM) - Use a combination of monitoring, cultural, biological, physical, and chemical controls to manage katydids effectively. Establish economic thresholds to determine when intervention is necessary, reducing unnecessary pesticide use. UC IPM Katydid Information
BINDWEED AND EFFECTIVE ERADICATION STRATEGIES
Bindweed, also known as Convolvulus arvensis, is a perennial vine notorious for its rapid growth and tenacity. Originating from Europe and Asia, it has spread widely and become a significant pest in gardens and agricultural fields worldwide. Identifying and understanding bindweed is crucial for effective control.
Problems Caused by Bindweed - Bindweed competes aggressively with crops and garden plants for sunlight, water, and nutrients. In agricultural settings, it can significantly reduce crop yields by overshadowing and strangling desirable plants. Its deep root system and ability to regenerate from small root fragments make it particularly difficult to eliminate.
Eradication Methods - Effective eradication of bindweed requires a combination of methods, persistence, and timing.
- Regularly pulling or digging out young bindweed can be effective, especially for small infestations. It's crucial to remove as much of the root system as possible. Unfortunately, it is rare to remove the entire root system. This method is labor-intensive and often needs to be repeated multiple times throughout the growing season.
- Applying a thick layer of mulch can help suppress bindweed by blocking sunlight. Organic mulches like straw or wood chips can be used. Mulching is more effective when combined with other control methods.
- Soil Solarization involves covering the soil with clear plastic during the hottest part of the year. The heat generated under the plastic can kill bindweed seeds and roots. This method works best in sunny, warm climates and requires the plastic to be in place for 4-6 weeks.
- Chemical control can be effective, particularly for large infestations. Glyphosate-based herbicides are commonly used, as they are absorbed by the leaves and transported to the roots, killing the plant systemically. Care should be taken to follow the manufacturer's instructions and to minimize impact on non-target plants and the environment.
Continuous Monitoring - Eradicating bindweed is not a one-time task but a long-term commitment. Continuous monitoring and repeated application of control measures are necessary to keep this resilient plant at bay. By combining different methods and remaining vigilant, gardeners and farmers can successfully manage and reduce bindweed infestations UC IPM Bindweed Pest Note
DEBUNKING 11 COMMON MYTHS ABOUT BLOSSOM END ROT IN TOMATOES
One of the most frequently asked questions on social media and to Master Gardeners is, “What is wrong with my tomatoes?” Unfortunately, there's a lot of misinformation out there, making it crucial to debunk some common garden myths. Blossom end rot (BER) is a prevalent issue in tomato cultivation, and it is surrounded by numerous myths and misconceptions. In this article, we'll explore some of the most common myths about blossom end rot and uncover the truths behind them. As you'll see, a consistent theme emerges in all the answers.
2. Myth: Adding more calcium to the soil will immediately fix BER. Reality: While calcium deficiency in the fruit is a factor, simply adding more calcium to the soil does not solve the problem. The issue is due to the plant's inability to uptake calcium efficiently, which is affected by inconsistent watering, root damage, or other stressors. Ensuring consistent soil moisture is more effective than adding calcium supplements.
3. Myth: All tomato varieties are equally susceptible to BER. Reality: Some tomato varieties are more prone to BER than others. Plum and paste tomatoes, for instance, are often more susceptible. Choosing resistant varieties can help reduce the occurrence of BER.
4. Myth: Place a Tums antacid along with your tomato transplant when planting to prevent BER. Reality: While it is true that calcium is important for preventing BER, the issue is due to the plant's inability to uptake calcium consistently rather than a lack of calcium in the soil. Factors such as irregular watering, root damage, and extreme weather conditions can interfere with calcium uptake.
5. Myth: Overhead watering causes BER. Reality: While overhead watering is not recommended for various reasons, it in itself does not cause BER. The disorder is related to the plant's calcium uptake and not directly to the method of watering. However, inconsistent watering practices can contribute to BER.
6. Myth: BER is caused by too much or too little sunlight. Reality: BER is not directly caused by sunlight levels. While proper sunlight is crucial for healthy tomato growth, BER is primarily influenced by calcium availability and water management.
7. Myth: Using Epsom salts prevents BER. Reality: Epsom salts are magnesium sulfate, and while magnesium is an important nutrient for plants, it does not prevent or cure blossom end rot. In fact, excessive magnesium can interfere with calcium uptake. Proper soil testing and balanced fertilization are key, along with proper watering.
8. Myth: BER can be cured by applying calcium sprays to the foliage. Reality: Foliar calcium sprays have no effectiveness in addressing BER because the disorder occurs due to a calcium deficiency within the fruit itself. Ensuring that the plant has access to calcium through its root system via consistent soil moisture is required.
9. Myth: Once a tomato fruit has BER, it can recover. Reality: Affected fruits will not recover from BER. The damaged tissue remains, although new fruits can develop without BER if the underlying issues are addressed with proper watering practices and soil management.
10. Myth: Using mulch will prevent BER. Reality: Mulching can help by maintaining consistent soil moisture, which can reduce the occurrence of BER. However, mulch alone is not a cure-all. Proper watering practices and soil management are also crucial.
11. Myth: BER is only a problem for tomatoes. Reality: BER can also affect other fruiting vegetables like peppers, eggplants, and squash. The underlying causes and prevention methods are similar across these plants.
By understanding these myths and focusing on consistent watering practices, balanced fertilization, and choosing resistant varieties, gardeners can effectively manage and reduce the incidence of blossom end rot in their tomato plants. UCCE BER PUBLICATION
Resource Links Referenced in this Article:
KatydidUC IPM Katydid Information
Field BindweedUC IPM Field Bindweed Information
Managing Blossom-End Rot in Tomatoes and PeppersUCCE Nevada & Placer County Publication 31-050C
The classic answer is, “It depends.” Some of the variables to consider are soil texture and structure, plant choice, season, weather, amount of sunlight and wind, and how well established the plant is. With so many variables, the answer to this question is not simple. The appearance of a plant can suggest a water deficit, but appearance alone is not a reliable indicator of water needs. Unfortunately, many of the symptoms of water deficit— slow growth, wilting, leaf drop, branch dieback, and death—are similar to symptoms of a lack of oxygen, which is commonly caused by overwatering. Other conditions can also cause similar symptoms: root disease, insect injury, herbicide injury, and others. If you suspect your plant's symptoms are caused by lack of water but they don't improve within 24 hours of watering, or if the soil is moist, water deficit is not the cause and you will need to investigate other causes.
General Irrigation Guidelines
Some general guidelines for irrigation are to water early in the morning, to water around the drip line of the plant rather than close to the trunk, to put plants with similar water needs together (hydrozone) and to add a 1'-3” layer of mulch to help keep the soil moist. Roots are encouraged to grow if plants are watered deeply—enough to moisten the soil to just beyond the root zone—and infrequently, rather than shallowly and frequently. A hygrometer, or soil moisture meter, is useful for measuring moisture at the root zone. Follow the directions for use to avoid inaccurate readings.
How will you know how deep the roots are for a particular plant? One way is to carefully dig down to sample the soil around the plant to determine the depth of the roots. An alternative is to estimate the depth of the roots based on the type of plant. The California Master Gardener Handbook gives these ranges for root depth:
- Leafy vegetables and annual bedding plants: top 6 inches to 1 foot
- Cool season turfgrass and flowering perennials: top 6 inches to 1 ½ feet
- Shrubs, trees, ground covers, vines, warm-season turfgrass, and most non-leafy vegetable crops: top 1 to 6 feet (p. 94)
In this article, the focus is on irrigating trees and shrubs, not turf, which is a different situation. The general guidelines above are sufficient in many instances, but you may want a more precise answer for specific plants. Many gardeners tend to overwater rather than underwater; taking the guesswork out of watering can help prevent this.
What is WUCOLS IV?
Fortunately, we have online resources to help determine water needs. The Water Use Classification of Landscape Species, 4th Edition (WUCOLS IV), has been developed by the UC Davis California Center for Urban Horticulture with input from a variety of horticultural professionals. A total of 3,546 species in six different climate regions in California have been evaluated for water needs. San Joaquin County is included in the Central Valley region. The WUCOLS Users Manuel introduces the system; it should be read first to better understand the system. One useful feature of the WUCOLS searchable database is that it allows you to create an overall landscape plan or hydrozone for a portion of a landscape by generating a list of plants specific to your area with similar water needs. But this article will focus on how it can be used to determine the water needs for a particular plant.
It is important to note that the recommended amounts of water given in the WUCOLS database apply only to standard growing conditions, so they do not apply to plants in pots, for instance. These standard growing conditions limit the results to well-established plants growing in the ground in full sun (except when it is a species that requires shade) without variables such as heat reflected from nearby buildings or pavement. The water needs of each plant are given as a percentage range of reference evapotranspiration (ET0).
Evapotranspiration is defined as the process by which water is transferred from the land to the atmosphere by evaporation from the soil and by transpiration from plants. More simply for these purposes, it is the water use of a plant or a planted area. ET0 is a way of standardizing water requirements and is based on the amount of daily water used by 4-inch-tall cool-season turfgrass when soil water is unlimited. Keep in mind that ET0 is not the amount of water required by a plant to remain healthy—that amount is usually less— but rather a reference point. The WUCOLS IV Plant Search Database provides water requirements for each of the plants in its database in all six regions in California by giving the percentage of ET0 required, with species grouped in the following categories:
Category | Category | Percentage of ET0 |
High | H | 70-90 |
Moderate | M | 40-60 |
Low | L | 10-30 |
Very Low | VL | <10 |
In the example below, a Chinese pistache tree (Pistacia chinensis), requires a low amount of water in the Central Valley but a moderate amount in the Low Desert region. These classifications consider not only temperature, but additional factors such as wind or whether a species is planted outside of its native range, so sometimes the results seem counterintuitive. Here, for example, it is surprising that the tree would need less water in the Central Valley than in the South Coastal region.
How does CIMIS help?
Once you know the percentage of ET0, needed for a particular plant, the next determination is the ET0 in your area. San Joaquin County falls into two ET0 zones as defined by the California Irrigation Management Information System (CIMIS). The east side of San Joaquin County is in zone 12; the west side (roughly west of the San Joaquin River) is in zone 14.
(Figure 3)
CIMIS provides hourly, daily, and monthly reports of total ET0 and other useful data gathered from sites throughout California, as well as the monthly averages listed below in Figure 4.
Using This Information
Taking the Chinese pistache tree in Stockton (zone 12) as an example, we see that in the month of July it requires 10-30% of 8.06 inches of water, or 0.81” to 2.42”. This could be applied as a deep watering once during the month or divided into two waterings of 0.4” to 1.21” each. Sandy soil requires more frequent watering than clay soil, which doesn't drain as quickly.
How would you apply an inch of water to a tree? To determine this, two more steps are required. First, the size of the canopy of the tree or shrub indicates the number of square feet that require water. If the canopy is 10 feet in diameter, the radius is half of that, or 5 feet. The formula for determining the number of square feet in a circle is
Pi (3.14) x radius squared = square feet
Thus, a tree with a diameter of 10 feet has a radius of 5 feet, and the calculation would be
3.14 x (52) = 78.5 square feet.
Next, given that 0.62 gallons of water provides an inch of water per square foot, you can calculate how many gallons to provide. Following the above example of a tree canopy that covers 78.5 square feet, if you determine that the tree needs 1.62 inches of water (20% ET0) in July, use the following formula to convert inches of water into gallons:
Square feet x inches of water x 0.62 = gallons of water
In this example, the tree canopy is 78.5 square feet, and it needs an average of 1.62 inches of water in the month of July, so you would calculate 78.5 x 1.62 x 0.62 = 78.85 gallons. If you divided that into two waterings during the month, you would apply 39.5 gallons at each watering.
How will you measure the number of gallons you are applying? Drip system emitters are labeled with the amount of water they deliver per hour—usually 1-3 gallons, so the number of emitters per plant would determine how long to water. When using a garden hose, one way to determine how much water you are applying is to turn on the water to the force you plan to use—remembering that watering “low and slow” is best because it allows the water to sink in. Next, measure how much time it talks to fill a gallon container. A slow trickle may require 4 minutes to fill a gallon container. Then, for instance, if you determine your tree needs 40 gallons of water and it takes 4 minutes to apply a gallon of water, you will have to water for 160 minutes to achieve that. It is also possible to purchase a flow meter that can be attached to your hose that gives a digital readout of the flow rate and total water emitted. This is a more precise way of measuring, and you can vary the flow rate while still measuring the total amount applied. When watering under a large tree canopy, it is best to water apply water at the drip line or with a soaker hose arranged in a spiral as in Figure 1 above.
Keep in mind that the final number you arrive at is just a starting point. Your plant or tree will require less water if it is in partial shade and more if it is affected by light reflected off cement or asphalt, for instance, so careful observation is still necessary.
Following the general guidelines for watering are useful, but you may wish to delve deeper into the question of how much water to give your plants by going “into the weeds” and using more precise methods. This may seem like a lot of work, but if you are trying to keep valuable trees and shrubs healthy while conserving water, taking advantage of these carefully developed resources can help you do that. Determining the appropriate amount of water for your plants is more important than ever, as water becomes an increasingly scarce resource.
References:
California Irrigation Management Information System: Reference Evapotranspiration Zones
Laurence, R.C., et al. 2003. Abiotic Disorders of Landscape Plants: A Diagnostic Guide. University of California, Agriculture and Natural Resources Publication 3420.
Native Gardening 101: Watering Native Plants
Pittenger, D.R., ed. California Master Gardener Handbook, Second Edition. Chapter Four: Water Management. University of California, Agriculture and Natural Resources Publication 3382.
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