By Susanne von Rosenberg, UC Master Gardener of Napa County
When I first moved to Napa 14 years ago, autumn rains arrived fairly reliably around the middle of October. As we are all painfully aware now, autumn rains have been starting later and later…and sometimes not at all.
There is no rain in the near-term forecast, and the National Oceanographic and Atmospheric Administration (NOAA) Climate Predictions Center foresees a 33 percent chance of below-normal rainfall through November coupled with a 60 percent chance of above-normal temperatures. The longer-term prediction for our area is for slightly below-normal rainfall.
The change in rainfall pattern we've been experiencing, with rains coming later than they used to, is consistent with what climate-change models predict. While we can expect roughly the same amount of rain, we will wait longer for it and it will come in fewer, more intense events.
So we need to get used to longer dry seasons. On the other hand, we need to be prepared for heavy rains. How should we adjust our gardening practices to address this change?
Let's talk about an extended dry season first. It's definitely a good idea to continue all the water- conservation practices that we instituted during the last drought. Choose drought-tolerant plants, including natives that are adapted to summer-dry climates. Install proper irrigation systems, such as drip irrigation, to water only those plants that truly need it and in the amount they truly need.
Adjust your watering according to the season. With cooler, shorter autumn days, plants require less water, even if it isn't raining. Mulch your plants to keep the soil cool and reduce evaporation.
We also need to reconsider our fall watering habits. It used to be possible to stop watering trees by late August and many other plants by mid-September. With the change in climate, you now need to continue to water until the rains finally arrive. Also consider our fall heat and low-humidity periods. Look for signs that your plants need water. Drooping leaves and/or dull leaves are two primary indicators. Get to know how your plants show they are thirsty.
How much and how often should you water with this new climate? For annual plants, simply test the soil with your finger. If the soil feels moist one to two inches down, you do not need to water yet. Keep checking and you'll soon have a sense how much water your plants need in this cooler season and how quickly they dry out when we get Diablo winds.
For trees, you can either dig down six inches to see if the soil is dry (this is the best way to check), or simply extend the time between watering. If you were watering your trees once a month in the summer, you might wait five to six weeks for the next round, and then six to seven weeks (mid- to late November) for the next round. Still no rain by New Year's? It might be time to water again! Even our native and other drought-tolerant plants may need supplemental water when rains are delayed.
More frequent heavy rains are another outcome of climate change. We will need to be able manage more rainfall on our properties. Heavy rain can damage soil structure, wash away topsoil and produce standing water in low or poor-drainage areas. You can protect your soil structure by mulching. (Yet another benefit of mulching.) Observe how water flows on your property during a heavy rain. Your goal is to slow down the flow, which you can do by spreading it out, and also by including areas where you intentionally allow the water to pool and infiltrate. Overall, the better your soil, the more rainfall it can absorb and the more water it can hold. Organic mulches do wonders to improve your soil – so, yes, keep mulching.
After a heavy rain, you may see water pooling in areas where you don't want it. In that case, you need to improve the drainage in that area. The best approach is to divert water from that area and to create additional opportunities for water to drain away. You can raise the soil level, dig small swales or create shallow berms. Small changes can make a big difference. You may also find, as I have, that as you improve the soil, your standing-water problem will diminish and eventually disappear.
Gardeners are a resilient and persistent bunch. With preparation, we can manage some of these climate-change challenges.
The UC Master Gardeners of Napa County are volunteers who provide UC research-based information on home gardening and answer your questions. To find out more about upcoming programs or to ask a garden question, visit the Master Gardener website (http://napamg.ucanr.edu) or call (707) 253-4221 between 9 a.m. and noon on Mondays, Wednesdays or Fridays.
- Author: T. Eric Nightingale
Planning a drought-tolerant garden can be a challenging endeavor. Knowing which plants to use and where to plant them is difficult as information and advice can vary significantly. However, there are a few simple things you can do to make the process easier.
The first task is to become intimately acquainted with your garden. Watch the way the sun moves and where the shade falls throughout the day. It may seem obvious that how much sun a plant receives will affect how much water it uses, but not all plants labeled for low water use will thrive in full sun.
Knowing the locations in your garden that receive shade from summer heat can greatly affect the health of your plants and the maintenance required to keep them looking attractive.
Note how wind moves through your garden. Evapotranspiration, the loss of water through plant leaves, increases significantly with high, hot or dry winds. On a cloudy yet windy day the plants in your garden could dehydrate more than you expect.
Finally, get up close and personal with your soil. Check its water retention by digging a hole about a foot deep and wide and filling it with water. Hope for the water to percolate through in about an hour, signifying good drainage.
Many drought-tolerant plants, especially succulents and cacti, will rot if soil drains too slowly. Conversely, if the soil drains too readily, it can be difficult to keep even low-water plants adequately hydrated.
All of these factors will help you form a picture of how water will be utilized in, and move through, your garden. This knowledge is a useful tool when choosing new plants.
When working on creating a drought-tolerant garden there are some preconceptions it is best to discard. When many people think of a garden, the image that comes to mind is of a classic English garden. This is understandable as modern home gardening and many of its traditions originated in Europe.
But England has a different climate than Napa, and it is not realistic to expect our gardens to look like English landscapes.The plants found in English gardens are often not good candidates for a Napa Valley garden, least of all a drought-tolerant one.
Many of the best-known annual plants are thirsty in our climate, as are many popular perennials such as hydrangeas, camellias and gardenias. Tropical plants, while visually stunning, are often troublesome as well. Even if they are not labeled as requiring a lot of water, the relatively low humidity in Napa Valley can make it difficult to keep them healthy.
Changing our expectations for our gardens does not mean lowering them. A garden can use less water and remain visually pleasing, lush and colorful. In a sunny location, shrubs such as salvia and lavender can be placed among large succulents such as aloe and agave. The contrast of soft and sharp textures is pleasing to the eye. The salvia will bloom most of the summer, while many aloe, such as Aloe capitate, bloom in the winter.
Many popular groundcover-type plants have shallow roots and need frequent watering. These can be easily replaced by a clumping or vining succulent. A favorite of mine is ice plant, Delosperma cooperi, which produces a carpet of purple-pink blooms from spring through summer.
Identifying plants that work in a drought-tolerant garden is easy after some practice. Generally speaking, plants with large, glossy leaves are a poor choice. These plants will lose a lot of water to evapotranspiration and are prone to sunburn. Plants with dusty or fuzzy-looking leaves are much more adapted to hot, dry conditions.
The roots of a plant can also tell you something about its water needs. Small, shallow roots will need more frequent watering than large, deep-burrowing ones. Never hesitate to gently remove a nursery plant from its pot and inspect the roots. They are a key indicator of plant health.
An important bit of information often missing on plant labels is the term “once established in the ground.” Succulents excepted, a potted plant will usually need more water and fertilizer than the same plant in the ground. Many drought-tolerant shrubs survive by growing broad or deep root systems. It takes at least a year for new plants to develop a useful root system, during which time they will need additional water.
Knowing these facts about your garden and the plants in them, as well as altering your perception of how a garden should look, can make an enormous difference in your relationship with it. You can minimize required maintenance and reduce your stress, leaving only the pleasure of enjoying the beautiful space you have created.
Next workshop: “Home Vineyard: Part 2” on Saturday, September 14, from 9:30 to 2:00 p.m., in Calistoga. Learn techniques to maintain your new or existing home vineyard. Workshop location will be provided after registration. For more details & online Registration go to http://napamg.ucanr.edu or call 707-253-4221.
The UC Master Gardeners are volunteers who provide UC research-based information on home gardening and answer your questions. To find out more about upcoming programs or to ask a garden question, visit the Master Gardener website (http://napamg.ucanr.edu) or call (707) 253-4221 between 9 a.m. and noon on Mondays, Wednesdays or Fridays.
For now, I've turned my energies to creating a rain garden in an area of my yard that tends to produce runoff. In wet weather, this silty water flows onto the sidewalk and then into the street. The plans that I perused required creating a declivity or basin filled with and surrounded by foliage and larger rocks.
The rain garden is not a pond feature; it is actually dry most of the time. It is intended to hold water only briefly during and after a rain, allowing water to filter slowly through the soil and rocks.
People have collected rainwater since ancient times, but the modern rain-garden concept originated in Prince George's County, Maryland, in 1990. By keeping water off the sidewalks and out of the streets,a rain-retention basin reduces the flow of contaminated water into storm drains. It slows the water flow, allowing soil and plants to break down and filter out the pollutants.
Select your location carefully. Look for a natural declivity or a flat place that receives water from a downspout or overland flow during a storm. You can construct a rain garden on a hill but that requires more digging. Avoid locating it over a septic system or near tree roots. Also consider how the nearby landscape plants might adapt to the new watering regime. Finally, avoid underground pipes and pick an area that gets full or partial sun.
Choose a design that complements your existing landscape. Size depends on the collection surface; a 1,000-square-foot rooftop requires at least a 200-square-foot garden. The garden should be able to hold an inch of rain at one time.
In our mediterranean-type climate, we can expect little or no rainfall for at least six months every year. With that in mind, choose native or drought-tolerant plants. Those plants in the basin and the ones on the berm will have different water access so plan accordingly.
You will have to water your plantings for the first year or so, until they get established. Mulch them with a heavy material,such as shredded wood or wood chips, that won't float away during the flooded periods.
The area under consideration in my yard was actually a raised mound. After a rain there was always a mud slick on the sidewalk that filled up the parking strip and then flowed into the street.
The hiccup in my plans was when I realized that I would have to remove and dispose of an astronomical amount of soil. So I had to shelve the rain-garden concept. I solved the runoff problem by digging a two- by two-foot trench around the mound. As it was, I was hard put to find a home for just that amount of soil.
All my garden beds needed freshening, so I mixed the excavated soil with equal amounts of compost and topsoil. With that mixture, I fluffed up my planting beds. I then filled the resulting trench with about six inches of gravel and topped it off with two- by three-inch cobbles that matched the rest of my landscape. I now have created a so-called French drain around the problem location.
Although I am not using the water for irrigation, I hope that percolating the water through the rocks will cleanse it naturally. Based on the meager rains we've had since I completed the work, the water is definitely being re-routed. I no longer see a mud slick on the sidewalk. Instead, the trenches catch the runoff to refill the aquifer.
I was really looking forward to creating a rain garden, but you do the best you can with the situation you have. I planted a succulent garden on the remaining mound, which will help conserve water, and I am quite happy with the result
For more information on creating a rain garden, visit the website of the Watershed Information Center & Conservancy. Also check out the website of California Sea Grant (https://caseagrant.ucsd.edu/sites/default/files/GS3%20Rain%20Gardens_8-10-09.pdf.)
Workshop: Napa County Master Gardeners will lead a workshop on “Drought-Tolerant and California Native Plants” on Saturday, August 1, from 9:30 a.m. to 11:30 a.m., at Martha Walker Garden in Skyline Park in Napa. Enjoy a walk around the garden to observe drought-tolerant and native plants, and discover the elements that help them thrive in our mediterranean climate. Learn how to use them in your own garden to replace some of those water-hungry ornamentals. On-line registration (credit card only) Mail-in registration (cash or check only)
Master Gardeners are volunteers who help the University of California reach the gardening public with home gardening information. Napa County Master Gardeners ( http://ucanr.org/ucmgnapa/) are available to answer gardening questions in person or by phone, Monday, Wednesday and Friday, 9 a.m. to Noon, at the U. C. Cooperative Extension office, 1710 Soscol Avenue, Suite 4, Napa, 707-253-4143, or from outside City of Napa toll-free at 877-279-3065. Or e-mail your garden questions by following the guidelines on our web site. Click on Napa, then on Have Garden Questions? Find us on Facebook under UC Master Gardeners of Napa County.
For most of my life, I have not been an edible gardener. Flowers and shrubs were my interest. But when I became a Napa County Master Gardener, I wanted to see what all the hoopla was about, so I purchased a single tomato plant at our yearly tomato sale.
I found a happy spot for it in the garden and just stood back and watched it grow and grow and grow. I had no clue how much one plant would yield. It was not unusual for me to get a large bowl of tomatoes every other day at peak production.
By the end of the season I was completely overwhelmed with tomatoes. So now I understand the locked-doors story. To my surprise, my husband recently found a use for the surplus yellow tomato slices that I had stored in our freezer. He announced that the “lemon slices” were just the ticket in his iced tea.
A single zucchini plant can yield three to nine pounds of squash. I have seen zucchini in my mother's garden that seemed to double in size overnight. Considering that a single zucchini plant can cover six feet of ground, I wonder why anyone would ever want more than one.
A tomato plant can grow five feet tall and just as wide and produce 10 to 15 pounds of fruit in a season. A study done by Purdue University Cooperative Extension found that 25 strawberry plants could yield 25 to 50 quarts of berries between mid-May and late summer. A standard-sized apple tree can produce 10 to 20 bushels of fruit.
A single family can eat just so much produce. What can be done with the surplus?
For people of my parents' generation, who experienced the Great Depression and World War II, preserving food was de rigueur. They learned how to do so early in their lives and continued to can, freeze, pickle and sometimes dry their excess produce throughout their adult years.
But at least in my circle of acquaintances, folks don't seem to enjoy these activities as much anymore. Over the years, I have frequently seen large canning pots, preserving jars and accouterments for canning in secondhand stores. Not recently though.
We seem to be experiencing a resurgence of interest in food preservation. Two years ago, my niece quit her job to stay home and raise her two boys. She and her husband turned their entire yard into an edible garden. She cans, dehydrates and freezes fruits and vegetables all year long. She and her family reap the rewards on so many levels.
If you are interested in food preservation but don't know where to begin, you can find some resources online. Sacramento County has a Master Food Preserver program. Check the web site (http://cesacramento.ucanr.edu/Master_Food_Preservers_181/) forthe schedule of workshops and classes.
When you are planning your fall garden, make sure to have a strategy in place to preserve your excess. Otherwise you just might be that person in stealth gear leaving overflowing bags of produce in the cars or on the front porches of your neighbors.
Workshop: Napa County Master Gardeners will lead a workshop on “Drought-Tolerant and California Native Plants” on Saturday, August 1, from 9:30 a.m. to 11:30 a.m., at Martha Walker Garden in Skyline Park in Napa. Enjoy a walk around the garden to observe drought-tolerant and native plants, and discover the elements that help them thrive in our Mediterranean climate. Learn how to use them in your own garden to replace some of those water-hungry ornamentals.On-line registration (credit card only) Mail-in registration (cash or check only)
Master Gardeners are volunteers who help the University of California reach the gardening public with home gardening information. Napa County Master Gardeners ( http://ucanr.org/ucmgnapa/) are available to answer gardening questions in person or by phone, Monday, Wednesday and Friday, 9 a.m. to Noon, at the U. C. Cooperative Extension office, 1710 Soscol Avenue, Suite 4, Napa, 707-253-4143, or from outside City of Napa toll-free at 877-279-3065. Or e-mail your garden questions by following the guidelines on our web site. Click on Napa, then on Have Garden Questions? Find us on Facebook under UC Master Gardeners of Napa County.
The so-called sticky monkey flowers have leaves with a sticky feel to them, and they sort of grab you. These are native to southern Oregon, California and Baja California. Once established, they do well without summer water.
In the midst of a recent heat wave, I walked around to take a look at my plants. I noted lots of dead wood on the monkey flowers but they still had leaves on the tips. They had not had water since the last rain. Perhaps if I had kept them pruned closer to the ground and cut the dead wood back, the heat wave would not have affected them quite as much. I will see how this approach works next year. The ones in the ground have mostly yellow and light-orange flowers.
I also have non-sticky monkeys in pots, and they are all doing well as they receive regular water. They are not drought tolerant. These bloom in a variety of colors, and some are hybrids. One of my favorites is ‘Spunky Monkey' (Mimulusnaiandinus ‘Mega'). The upper petals are violet pink and the lower petal is white with pink dots. This variety dies down during winter but reseeds easily within the confines of the pot.
Another variety that I really like is ‘Pamela.' It is yellow with white trim around each petal. It blooms over a long period and overwinters well in a pot.
Monkey flowers can be propagated from cuttings. Cut off a healthy growing tip 4 to 6 inches long. Strip off the bottom leaves and put the stem in a moist growing medium. The cutting should root in about two months. If you tug gently and feel resistance, your cutting has rooted. After a few months, replant in a larger pot with potting soil and place in part sun.
You can find many images of monkey flowers online and information about each variety.
Monkey flowers form a seed pod when the flowers have finished blooming. You can collect the seed and start seedlings in early spring, or you can buy seed. Seeds need chilling before they will germinate. The chill causes the seed covering to crack.
To germinate seeds, put them on a damp paper towel or dampened planting mix. If you use a paper towel, put it into a plastic bag. You may also press the seeds into the planting mix and seal the pot with a plastic bag. If the seeds need chilling, put them in the plastic bag in the refrigerator for a month or so. When you take them out of the refrigerator, they will think spring has arrived and germinate quickly. If you have them on the paper towel, press the towel into the planting mix and the roots will grow through the towel. Once the seeds have germinated, treat them like any other seedling by keeping them moist and dividing them once they get three to four leaves.
Native monkey flowers are good candidates for drought-tolerant landscapes. Occasional grooming is all they need. So if you are going to monkey around in the garden, give monkey flowers a try.
Free workshop: Napa County Master Gardeners will conduct a workshop on “Home Composting” on Saturday, September 6, from 9:00 a.m. to 10:00 a.m. at the Yountville Community Center. Learn how to turn yard waste and kitchen scraps into rich compost to use as a soil amendment or mulch in your garden. The workshop is free but Pre-registration is required. No phone registrations are accepted. You will receive a confirmation and directions after registering. Questions? Call (707) 257-9200.
Master Gardeners are volunteers who help the University of California reach the gardening public with home gardening information. Napa County Master Gardeners ( http://ucanr.org/ucmgnapa/) are available to answer gardening questions in person or by phone, Monday, Wednesday and Friday, 9 a.m. to Noon, at the U. C. Cooperative Extension office, 1710 Soscol Avenue, Suite 4, Napa, 707-253-4143, or from outside City of Napa toll-free at 877-279-3065. Or e-mail your garden questions by following the guidelines on our web site. Click on Napa, then on Have Garden Questions? Find us on Facebook under UC Master Gardeners of Napa County.
