By Dianne Weyna, UC Master Gardener of Napa County
There are many flowering trees in Napa's Fuller Park, and this spring would be a good time to see them in bloom. Fuller Park was acquired by the City of Napa in 1905, and in 1919 it was named after the mayor involved in its acquisition, C.H. Jack Fuller. The park is home to over 60 species of trees and is an example of an arboretum or “tree zoo,” having both native and non-native species.
UC Master Gardeners advocate planting native plants because natives are adapted to our conditions, but Fuller Park's tree collection is a resource to appreciate and learn from. If you'd like to learn more about these trees, join the UC Master Gardeners of Napa County on one of their Guided Tree Walks in Fuller Park, held monthly from April through October, on the second Tuesday of each month. Space is limited so please register online. The Napa County Master Gardener website also has information on doing a self-guided tour of Fuller Park's trees. You'll find other tree resources on the website, including Trees to Know in Napa Valley by UC Master Gardeners, available for purchase online or from the Napa County Master Gardener office at 1710 Soscol Avenue, Suite 4, in Napa.
Here's a preview of what you'll see on the walking tour, starting at the corner of Oak Street and Seminary Street. There you'll find the Eastern redbud (Cercis canadensis), a deciduous tree that sports pink flowers in spring and heart-shaped leaves in summer. By autumn, the redbud has seed pods along its branches. It's a great street tree as it doesn't grow too large and the roots are not obtrusive.
I have a redbud tree, and it is full of buzzing bees in the spring. My tree grows straight up, not bent like the one in Fuller Park. The native Western redbud (Cercis occidentalis) is similar to the Eastern redbud. Both can be grown as shrubs or trees and have low water requirements.
The tallest tree native to the eastern U.S., at 191 feet, is a tulip tree (Liriodendron tulipifera) in the Great Smoky Mountains National Park in North Carolina. The one at Fuller Park is much younger and smaller. The tree is in the magnolia family, but its flowers are high in the canopy and not as conspicuous or aromatic as magnolia flowers. The tulip-shaped flowers are light yellow with an orange center. They produce large amounts of nectar in the spring and many seeds in the fall. I have one of these trees in my yard and often pull up seedlings. The leaves turn yellow in the fall and are described as goosefoot shaped.
Near the Laurel Street side of the park is the red horse-chestnut (Aesculus x carnea) a cross between a horse-chestnut (A. hippocastanum) and a red buckeye (A. pavia). The seeds are poisonous but were eaten by Native Americans after boiling them to leach the toxins. Flowers are bright red and fragrant, attractive to bees and hummingbirds. The California buckeye (A. californica), a small deciduous tree that also produces flowers, is common in Napa Valley.
The chitalpa (Chitalpa tashkentensis) was hybridized in 1964 in Tashkent, the capital of Uzbekistan, and brought to the U.S. in 1977. This tree is a cross between two U.S. native flowering trees, the Southern catalpa (Catalpa bignonioides) from the southeastern U.S. and the Southwestern desert willow (Chilopsis linearis). Flowers are light colored and fragrant. It is drought tolerant and can take full sun, but the bark can get sun scald.
The jacaranda (Jacaranda mimosifolia) is native to Argentina and Bolivia and is in the same family as the chitalpa and trumpet vines. It produces aromatic blue-lavender flowers and is common in Southern California and warmer areas worldwide. It is moderately drought tolerant. Although it grows fast in the tropics and is considered invasive in some areas, it is a slower grower in our climate. Jacaranda makes a good shade tree.
Another Eastern U.S. native growing at Fuller Park is the Washington hawthorne (Crataegus phaenopyrum). This tree produces clusters of white booms in the spring that are replaced with red berries in the fall. I personally do not like the smell of the blossoms but bees love it, and many species of birds like the berries. The attractive leaves are triangular and toothed, turning red in the fall. I have a Washington hawthorne as a street tree, where it works well.
On the corner of Oak and Jefferson Streets, notice the Dolgo crabapple (Malus x Dolgo), a variety brought from Siberia in the late 1800s. The soft pink, fragrant buds produce white flowers that are self pollinating. Because the blooms last for weeks, it is considered a universal pollinator, helping to pollinate other apple trees. The fruit is large for a crabapple and can be used for jellies and sauces or eaten fresh.
As mentioned, many of the Fuller Park trees are native to other areas. Napa doesn't provide the ideal environment for their optimal growth. When you plant new trees or shrubs, please consider our native insects and birds. They are in peril and rely on native plants for food and shelter.
Gardening with the Masters: Napa County Master Gardeners and Ole Health are presenting a gardening class on Saturday, March 19, from 10 a.m. to 1 p.m. at Ole Health's Garden at 300 Hartle Court in Napa. Space is limited. Register at https://bit.ly/3sxOpg9.
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 https://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
Most gardeners appreciate wildlife, even if we don't always appreciate what wildlife may do to cherished parts of our garden. There are many ways to support wildlife in our gardens, including planting pollinator plants for insects (especially plants that flower in the late fall, winter and early spring), planting seed or berry-bearing plants for birds, and allowing squirrels and other critters a share of your fruit and nut harvest.
The most important thing you can do for wildlife, however, is to provide consistent access to water. The best way depends on the types of wildlife you'd like to support.
We gardeners spend a good bit of time trying to protect plants from wildlife depredation, so it may seem contrary to invite wildlife into the garden. But I feel strongly that your garden and the planet will be enriched by encouraging wildlife to visit your garden.
Many insects get all of the water they need from their food sources, but it may surprise you to learn that some, including bees and butterflies, need water. You can actually train bees to prefer a certain water source by setting it up early in the year. By the time they really need the water, they are accustomed to coming to the location you selected.
The best options are shallow containers, such as a plant drainage saucer or a shallow bird bath, filled with rocks or other landing places. Bees prefer water with minerals in it (some sources refer to it as “dirty water”), so it's helpful to let some of the algae or leaves that fall into the water stay there.
Drain the water every few days to avoid mosquito breeding. (Mosquito eggs can hatch in 72 to 96 hours.) If you see what appear to be tiny tadpoles in your water, those are most likely mosquito larvae. Just drain the water to kill them. Bees find their preferred water source by scent, so it's best to keep the water source away from strongly scented flowers.
Butterflies can also use the bee water station but prefer to drink muddy water. The easiest way to create a puddling station is to fill a shallow container with a mixture of half sand and half garden soil or compost. Keep the mixture moist but avoid standing water, or drain water off regularly to avoid mosquitos.
You can also create a puddling area directly in the ground by creating a shallow depression, lining it with an impermeable liner and then filling it with equal parts sand and soil. Keep the area damp with a hose or by adding a drip emitter. The damp soil leaches minerals into the water, and the butterflies obtain the minerals as they drink. Like bees, butterflies need these minerals. Male Monarchs need the minerals to make pheromones, and females need them to support egg laying.
Birds need water for drinking and bathing. One of my favorite sights is watching small birds splash around in the shallow birdbath on my front porch. Keeping your bird bath in the shade keeps the water cooler and fresher. Birds appreciate nearby trees or bushes so they can preen after they bathe.
The ideal bird bath slopes from a depth of no more than 1 inch to a depth of no more than 2 inches. Small birds use the shallower edges, and larger birds such as jays like the deeper areas. Add a few rocks or pebbles for birds to land on, which also helps them judge the depth of the water. Birds will not enter water when they cannot tell how deep it is. Rocks or sticks that extend above the water surface will also allow insects to escape.
Change the water every one to two days. Birds leave debris and possibly droppings, so the water becomes unsanitary. You can use the birdbath water on your plants as long as you keep it away from any edible plant parts.
Small mammals, including squirrels, possums, raccoons, foxes and rabbits, are part of a balanced garden ecosystem. Although we frequently think of them as nuisances, they help keep insect populations under control. Also, if you like to watch birds of prey, you need small mammals in your garden to attract them.
Providing a water source encourages small mammals. A birdbath that is too deep for birds, a small pond or even a water dish can benefit these animals. Change the water frequently to avoid mosquito breeding. For ponds, use mosquito fish or an environmentally-friendly Bacillus thuringiensis israelensis (Bti)-based larvicide. Never release mosquito fish into natural water bodies. These fish aren't native to California and can disrupt ecosystems.
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 https://napamg.ucanr.edu or find us on Facebook or Instagram, UC Master Gardeners of Napa County.
by Rainer Hoenicke, UC Master Gardener of Napa County
As I looked east toward Atlas Peak and Mt. George on a particularly beautiful, clear morning while hiking with my dog recently, I felt immensely grateful to live in a place so richly blessed with trees. Napa's many large trees almost obscure the cityscape in older neighborhoods and provide shade on hot summer days, habitat for birds and other tree-dwelling wildlife, and a sense of wellbeing.
In my own neighborhood, almost every yard is graced with trees that were probably planted when the subdivision was built in the early 1970s. Most homeowners probably recognize the value of these trees to their small patch of land yet may not think much about what these trees contribute to the larger landscape.
One mission of the Master Gardeners is to extend research-based knowledge on sustainable landscape practices and natural ecosystems. Our own gardening activities affect not just our own well-being. They have benefits far beyond our fencelines and will benefit us for decades to come.
As I looked out over Napa that morning, I felt compelled to share my thoughts as an avid gardener. What do trees provide that goes beyond mere beauty and a sense of wellbeing?
Usually, more than half of a tree's weight is below ground. Tree roots form a dense network of living carbon that supports the soil ecosystem: the fungi, bacteria and other microorganisms that act together to cycle nutrients and contribute to soil fertility and health.
The roots of my yard's trees and shrubs contribute to good soil structure, nourish soil organisms and store carbon. Through photosynthesis, my trees and shrubs move carbon from the atmosphere into the soil. Trees take in carbon dioxide in their canopy, release oxygen and store carbon in their wood. They lock it away in their trunk, crown and roots throughout their long lives.
Plants with beneficial fungi growing in association with the roots are more resilient in times of drought. They are capable of tying up more carbon dioxide from the atmosphere as carbon in the soil, beyond what is contained in a plant's root mass.
Recent research suggests that coastal redwoods remove and store more carbon from the atmosphere per acre than any other forests on the planet.
“The carbon part of a redwood may be more important than the lumber part in the coming decades,” says Robert Van Pelt, a scientist at the University of Washington. In gardening terms, there may come a time when maintaining a redwood tree may be more important than increasing the size of your vegetable beds or rose garden.
While giant redwoods with their shallow root systems may not be appropriate for many smaller urban backyards, we see quite a few of them on larger parcels in Napa as well as in public parks. Our oaks are likely not far behind in storing carbon and compensating for carbon dioxide emissions.
If we want to reduce or even just stabilize temperatures in this time of rapid climate change, keeping our urban forests intact and thriving is an action we all can take.
Trees provide many other services we are often not aware of. They protect public health by reducing air pollution, provide natural air conditioning and increase our real estate values.
The City of Napa, with its long tree heritage, operates a little-known program to protect the community's most important trees. The Napa Registry of Significant Trees enables landowners to nominate trees on their property to be designated as “significant” by the City Council, so they can be preserved with all their benefits and recorded on the property's deed. Once recorded, a Significant Tree can only be removed if a permit is obtained that meets criteria outlined in the Napa Municipal Code.
The registry was established before many people understood the important role urban forests play in climate stabilization and carbon dioxide reduction. Most towns in Napa County have some kind of tree-protection policies in place, although some ordinances are more protective than others. Even with such regulations in place, we all need reminding that trees, so often taken for granted, contribute to our community heritage, enhance veggie-bed fertility and water use efficiency and help keep Napa livable for future generations.
Workshop: Napa County Master Gardeners will hold a workshop on “Weed ID, Frost Protection and Drip Irrigation” on Saturday, February 26, from 11 a.m. to 1 p.m., at Las Flores Learning Garden, 4300 Linda Vista Avenue, Napa. Register: https://bit.ly/3J1QFl8
Workshop: Napa County Master Gardeners will hold a workshop on “How to Improve Home Vineyard Soil Health for Grape Quality and Climate Change” on Saturday, February 26, from 9 a.m. to 12:30 p.m. Whether the workshop will be in person or via Zoom is still being determined.
You must register to attend. Registrants will receive an email a few days before the event with the workshop location or Zoom link. Register at https://ucanr.edu/2022HomeVineyardSoilFeb
Workshop: Napa County Master Gardeners will hold a workshop on “Your Soil Can Save Us! Garden Soil and Climate Change” on Sunday, February 27, from 1 pm to 3 pm, at Yountville Community Center, 6516 Washington Street, Yountville. Details: https://napamg.ucanr.edu
Food Growing Forum: Napa County Master Gardeners will host a virtual forum on “Citrus” on Sunday, March 13, from 3 pm to 4 pm. Register to receive the Zoom link at https://surveys.ucanr.edu/survey.cfm?surveynumber=36261.
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 https://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
Winter isn't over, but in my garden it feels like spring has sprung. This is my favorite time of year. I discovered a bearded iris in bloom today, two months early and a great surprise.
The first thing on my to-do list in February is to weed. The weeds loved those early rains and now it is warming up. They need to be removed before they go to seed.
One weeding tool that works well for me is a weed torch or flame weeder made specifically for gardening. It uses a propane tank and a wand. You wave the flame over the weeds to kill them. It works best on small, young weeds growing in hardscape or gravel, and it doesn't damage the soil as many commercial herbicides may do.
Don't use a weed torch during dry spells or on hot, windy days. Keep the flame away from dead or brown material or flammable items like fencing. Wear sturdy shoes and have water nearby to stop any possible flare-ups. Some areas have bans on flame weeders, so check with your local fire department before investing in the equipment.
It's not too late to do sheet composting for weed control. You can find a lot of information about this method online. Basically, you are smothering the weeds by covering them with sheets of cardboard. If you want to plant something before the cardboard has decomposed, just cut a hole in it and dig your planting hole.
One year I experimented by planting half of my broccoli seedlings in soil covered by cardboard and the other half in uncovered soil. The plants in soil covered by cardboard did better.
If you haven't already done so, it's time to prune roses, fruit trees and other shrubs and trees. You can control growth better if you prune before the leaves and flowers come out in the spring.
Plant any bare-root trees and roses now. Remember to water them as they settle into their new home.
We know that drought conditions may continue so keep that in mind when planning your garden this year. Look online for information about the water-wise French intensive method of gardening. If you are planting a new landscape, consider California native plants, which tend to be drought resistant.
Snails and slugs are just beginning to appear so watch for their damage. You can purchase commercial products to control them or try some more homespun methods. One tactic is to lay a board down where you see damage. Snails and slugs like to crawl underneath, so the next day you can stand on the board and crush them. You can also pick them off by hand if you go out at night with a flashlight.
Snails and slugs are hermaphrodites, which means they all lay eggs. They lay about 80 eggs four times a year, so it's important to keep them under control.
If you have plants in pots, now it the time to repot them. Use fresh soil and trim the old roots to make room for new ones. Try to match the potting soil to the needs of the plants. Most container plants need soil that drains well.
It's also a good time to move any plant that's in the wrong place in your garden. To make sure the top and the root ball are in proportion, trim both back when you transplant.
Start seeds for summer vegetables and other plants in February and March. I use a commercial seedling mix for this process. It is especially designed for newly emerging plants.
Be sure to read the seed packets for sowing instructions. Some seeds take longer to sprout than others and some need to be planted deeper than others. Keep your newly planted seeds by a sunny window. If you have a heat lamp or a seed-heating pad, they will appreciate that special treatment and sprout more quickly. Keep the soil damp but not soggy to prevent seeds from rotting before they sprout. You can also make a mini hothouse by inverting a large bottle over your seedling pot.
If the dry weather continues, monitor your in-ground plants and container plants. If the soil is dry, it's time to water. I have noted that some of my pots have dried out even though it has been cool this winter. Also, if we have a hard freeze, plants will survive better if they have moisture. I know this from experience.
Food Growing Forum: Napa County Master Gardeners will host this forum on “Planning & Record Keeping and Crop Rotation” on Sunday, February 13, from 3 pm to 4 pm. Register to receive the Zoom link at https://ucanr.edu/2022FoodForumFeb.
Workshop: Napa County Master Gardeners will hold a workshop on “Weed ID, Frost Protection and Drip Irrigation” on Saturday, February 26, from 11 a.m. to 1 p.m., at Las Flores Learning Garden, 4300 Linda Vista Avenue, Napa. Register: https://bit.ly/3J1QFl8
Workshop: Napa County Master Gardeners will hold a workhop on “How to Improve Home Vineyard Soil Health for Grape Quality and Climate Change” on Saturday, February 26, from 9 a.m. to 12:30 p.m. Whether the workshop will be in person or via Zoom is still being determined.
You must register to attend. Registrants will receive an email a few days before the event with the workshop location or Zoom link. Register at https://ucanr.edu/2022HomeVineyardSoilFeb
Workshop: Napa County Master Gardeners will hold a workhop on “Your Soil Can Save Us! Garden Soil and Climate Change” on Sunday, February 27, from 1 pm to 3 pm, at Yountville Community Center, 6516 Washington Street, Yountville. Details: https://napamg.ucanr.edu
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 https://napamg.ucanr.edu or find us on Facebook or Instagram, UC Master Gardeners of Napa County.
By Pat Hitchcock, UC Master Gardener of Napa County
In 2021 the Napa Master Gardeners' field trials group decided to grow cauliflower, not just once but twice. The first round got started in January with seeding into flats or pots; seeding for a fall/winter crop commenced in August. In addition, we grew out extra plants in the fall and gave them away to members of the public.
We hoped to get firsthand experience to inform our book knowledge of growing cauliflower in Napa Valley. We wondered if the plants would mature in the time stated on seed packets, whether spring or fall planting resulted in higher quality produce, and what challenges home gardeners might face in growing cauliflower.
We chose three varieties of cauliflower to test: Amazing, a standard white cauliflower; Graffiti, a purple variety; and Veronica, a pale green Romanesco type. Besides making it easy to tell which plants were which, the differently colored varieties produced a rainbow of mature cauliflower when they formed heads.
Cauliflower is a cool-season crop. We sowed the seeds in time to have six-week-old plants for transplanting in early spring (mid-February) and again in mid-September. We figured the spring sowing would mature before it got too hot, and the fall/winter sowing would mature in December or January.
We started all of the plants from seed and experienced excellent germination for all varieties, with most sprouting within a week. When seedlings had a couple of true leaves, we repotted them from cell packs into four-inch pots to have room to grow. From that point on, a weekly dose of half-strength liquid fertilizer was helpful.
Seedlings need lots of light. Gardeners growing indoors used high-quality grow lights. Some gardeners kept seedlings in protected outdoor locations to get maximum sunlight, bringing them indoors during extreme weather (frosty temperatures, heat waves or rain). By the time the seedlings were six or seven weeks old, they were a perfect size to transplant into garden beds.
For the spring trial, transplants were set out mid-February. They had no difficulty with our typical Napa early spring weather. Fall was a bit trickier. We had to navigate hot spells to set plants into the ground in mid-September. Though it was warm then, the plants would grow out when the weather was cooler. Some of us shaded the plants during hot spells.
Cauliflower benefits from fertilizer (following package directions) and full sun. Fertilized plants grew more luxuriantly and produced larger heads. Plants growing in shade were slower to produce and sometimes had smaller heads or did not produce at all. We also noted that our cauliflower plants were fairly large; they needed to be planted 18 to 24 inches apart to grow to full size.
All of our cauliflower varieties were supposed to mature in 75 to 85 days, starting from when transplants were set into the ground. The spring planting largely met that promise, with plants transplanted in February producing heads in late April and May. Fall transplants took significantly longer, with most producing heads in January.
We surveyed members of the public who got free plants in the fall. About half were successful in getting a crop. While we weren't able to follow up with each one individually, some of those who did not get a crop suspected that their plants were not getting enough sunlight.
Almost everyone said they had issues with aphids. You can control these pests by inspecting your plants regularly, especially the underside of leaves, and using a spray of water to wash them off. Two other insect pests that plague cauliflower are the cabbage looper and the imported cabbage worm. The looper is larvae from a moth; the cabbage worm is the larvae of a small white butterfly. Many Master Gardeners used row cover to prevent these flying insects from reaching their plants to lay the eggs that hatch into the voracious larvae. For more about these pests, consult the University of California's Integrated Pest Management website.
Birds can also be a problem for cauliflower, and the best deterrent is a physical barrier such as row cover, cages, or netting.
For the home gardener, cauliflower can be a rewarding crop. Because one head is all you get from each plant, you can then make way for a warm-season vegetable like zucchini. Fall-planted cauliflower takes longer to head up but is welcome in winter, when leafy greens and roots dominate the vegetable patch.
We did not find significant differences in the quality of the cauliflower grown in different seasons. The Master Gardeners who grew plants in both seasons enjoyed their harvest and said they were likely to grow cauliflower again. We did not have a consensus as to a favorite variety, but people appreciated the beautiful purple hue of Graffiti and the fractal spiral of the Veronica. All of our cauliflower ended up being delicious.
Food Growing Forum: Napa County Master Gardeners will host this forum on “Planning & Record Keeping and Crop Rotation” on Sunday, February 13, from 3 pm to 4 pm. Register to receive the Zoom link at https://ucanr.edu/2022FoodForumFeb.
Workshop: Napa County Master Gardeners will hold a workshop on “How to Improve Home Vineyard Soil Health for Grape Quality and Climate Change” on Saturday, February 26, from 9 a.m. to 12:30 p.m. Whether the workshop will be in person or via Zoom is still being determined.
You must register to attend. Registrants will receive an email a few days before the event with the workshop location or Zoom link. Register at https://ucanr.edu/2022HomeVineyardSoilFeb
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 https://napamg.ucanr.edu or find us on Facebook or Instagram, UC Master Gardeners of Napa County.