By Penny Pawl, UC Master Gardener of Napa County
When you are planning your summer garden, remember the pollinators. Bees and other pollinators are in trouble in California and across the U.S. and need our help. They are nectar feeders so put in plenty of blooming plants for them.
Without pollinators we would lose many food crops. There are 1,000 species of California native bees. Twenty-six of these are bumblebees and most of the rest are solitary bees.
The pollinators native to our area have evolved with the native landscape so it's important to have some native plants in your garden. Pollinators include native bees and butterflies. Honeybees are not native to the United States but were introduced for their honey. However, other pollinators are just as effective. Let me introduce you to some of our native bees.
For several years, I have created nests for the native mason bees. These nests consist of pieces of wood with 3/8-inch holes drilled into them. The one they visit most is a piece of firewood. Mason bees have nested in it repeatedly. I know they were there because of the mud in each hole.
Last year I actually saw the bees leaving their nests and then returning. They are about to come out this spring to pollinate the fruit trees. They don't spend much time flying around before they start building new nests for their babies.
The mason bee creates its nest in long narrow tunnels within the wood. The bees do not make these tunnels; they find them and move in. So I drilled the holes for them. The bees pack the holes with pollen, lay an egg, pack in more pollen and lay another egg. They put three to five eggs per hole depending on the depth. When they are done laying, around the first of April, they seal the holes with mud. I know the nest is full when I see mud in every hole. The eggs hatch the following spring.
This year I did not move the nest to a sheltered location. It appears that woodpeckers have tried to drill out the nest. I will wait and see how much damage the birds have done by the end of March.
I have bumblebees in my garden every year. They especially love my ‘Hot Lips' salvia from Mexico. They spend all day gathering nectar and are gentle.
Bumblebees nest in the ground. You should always leave a cleared area in your garden for them; they will not nest in mulch. I often find their little mounds. When they are done digging, you cannot tell they were even there. They love one particular area of my garden that I always keep clear of mulch.
I also see a lot of carpenter bees, the big bees that drill for nectar in the back of the flower. They are gentle and you can observe what they are doing easily.
They can be destructive when they drill into untreated lumber. I had them in my hothouse one year. They had drilled all the way to the end of a 12-foot-long 4 x 2 board. I had to replace that wood and paint it with latex to keep them out. Putting steel wool in the holes will also stop them. They do need a place to lay their eggs, however.
The male carpenter bee is a big brown teddy bear. He has only one purpose: to pursue females. He does not sting. I had a visit from one a few years back and he hung around me for a while. Once their mating duty is done, they die.
Digger bees and squash bees both nest in the ground. Squash bees emerge to pollinate squash and gourds. They are only present when these plants are in bloom. Even so, I hand-pollinate my squash to make sure I get fruit.
Bumblebees are said to buzz tomatoes, which are self-pollinating. Just to be sure the flowers do pollinate, I shake the vines every morning when I do my walk-through.
To lure pollinators to your garden, plan to have a variety of plants blooming every month of the year.
Workshop: UC Master Gardeners of Napa County will hold a workshop on “Growing Tomatoes” on Saturday, April 6, from 9:30 a.m. to 11:30 a.m. at University of California Cooperative Extension, 1710 Soscol Avenue, Napa.
Join our experienced tomato growers for tips and tricks on cultivating perfect homegrown tomatoes. Learn the latest research on tomato cultivation and care, and discover new and heritage tomato varieties. You'll get all the information you need to grow delicious and beautiful tomatoes in your own large or small garden or in containers. Growing America's favorite garden fruit is not only fun and easy, but also the best way to acquire healthy food for you and your family. Online registration (credit card only); Mail-in/Walk-in registration (check only or drop off cash payment).
Master Gardeners are volunteers who help the University of California reach the gardening public with home gardening information. U. C. Master Gardeners of Napa County (http:/napamg.ucanr.edu) 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.

Few other vegetables are more representative of fall than pumpkins. Come October, mounds of pumpkins of various shapes and sizes are a common sight in Napa Valley. While they may seem to suddenly appear, pumpkins have a fairly long growing season. If you are considering growing pumpkins in your garden for a fall harvest, it's time to plant.
Pumpkins belong to a large botanical family that includes melons, cucumbers and other squash. Some tiny pumpkin varieties can fit in the palm of your hand. The record-setting types weigh in at over a ton. Pumpkins also come in shades beyond jack-o-lantern orange. For an unusual addition to your garden, seek out white, red or blue-skinned varieties.
One bonus of planting pumpkins is that they attract bees. Honeybees will happily do the work of pollination, but a garden with a range of plants will lure and nurture other bee species. Squash bees tend to fly early in the morning, before honeybees get going. You may never even know that they have visited your garden. To encourage squash bees, consider adopting a no-till regimen. Squash bees nest several inches below the soil, and frequent tilling can destroy their habitat and nesting populations.
It is a joy to watch pumpkins grow, but they do need space. If your garden has ample room, allowing the plants to ramble can help shade and cool the surrounding soil and prevent weeds from growing. Before planting, amend the soil with compost to get plants off to a healthy start. Plants can be started in small pots or direct-seeded. If you are aiming for maximum size, feed with a high-nitrogen fertilizer to stimulate leaf growth. When blooms appear and fruit set occurs, phosphorus and potassium become more important.
Once established, pumpkins grow fast. To promote larger pumpkins, select one or two good specimens and remove all others on the vine. This pruning will help the plant transfer nutrients to the remaining units.
Squash leaves can be susceptible to mildew. Irrigating with drip or soaker hose is preferable to overhead watering. Remove diseased leaves as soon as possible and do not overwater. Leaves may wilt on hot days but typically recover as the weather cools. If wilting persists, check to make sure plants have adequate water
Common pumpkin pests include cucumber beetles and vine borers. A home gardener can tolerate some damage rather than resorting to chemical sprays. Remember that pollinators and other beneficial insects might be frequenting the plant, too. Use light-permeable row covers to protect plants if an infestation is particularly heavy.
Trap crops can also help reduce insect damage by providing an alternative food source. Crop rotation can help by eliminating available food sources for future generations of pests. The University of California's Integrated Pest Management database is an excellent resource for pest- and disease-control advice.
Besides being delicious, pumpkins have other advantages for the home gardener. They can help minimize weed growth around taller plants such as sunflowers. Native Americans understood the wisdom of planting pumpkins with beans; the beans add nitrogen to the soil and pumpkins are heavy feeders. Many pumpkins store well and can provide tasty meals in winter when many vegetables are out of season.
You don't have to wait for the pumpkin to mature before enjoying the plant. The leaves are edible and can be cooked like spinach. Choose young, tender leaves for that purpose. Of course, the seeds are edible, too. Enjoy them roasted and salted to increase the food value of your crop, particularly if you have limited space. Saving seeds and swapping with friends can increase your garden's diversity with no extra expense.
Pumpkins grow well in Napa Valley. Consider planting a beautiful heirloom cultivar to enjoy as a table centerpiece in winter. Between the pumpkin's tasty flesh, its seeds and its nutritious leaves, this plant hits a triple.
Workshop: U.C. Master Gardeners of Napa County will hold a workshop on “Succulent Plant Success” on Saturday, July 7, from 9:30 a.m. to 11:30 a.m., at University of California Cooperative Extension, 1710 Soscol Avenue, Napa. Bring your love of succulents to this workshop dedicated to helping succulent gardeners grow the show-stopping plants we all hope for. Master Gardeners will show you the right kind of soil and containers and how to care for your succulents. They will also discuss myriad succulent types to help you make a succulent garden for yourself or to give as a gift. Please bring succulent cuttings you would like to share.Online registration (credit card only); Mail-in/Walk-in registration (check only or drop off cash payment).
Master Gardeners are volunteers who help the University of California reach the gardening public with home gardening information. U. C. Master Gardeners of Napa County ( http://ucanr.edu/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.
Recently I went into my vegetable garden to visit the squash bees. They come out every year at this time when plants in the Cucurbitaceae family bloom. Cucumbers, melons, squash and pumpkins are just a few of the cucurbits they visit to gather pollen. The males just hang around to breed so that the females can build a nest and lay eggs.
Squash bees are among the 1,600 bees native to California and just one of the many types of native bees that visit my garden. The female builds her nest in the ground so be sure to leave some ground bare of mulch or other coverings.
Napa County Master Gardeners began studying bees when reports emerged of the declining honeybee population. We learned that some bees like to nest in holes in wood, so several of us built nests out of wood. I made several. The one I made from a piece of log with a little roof on it has done the best. It's a nest for mason bees.
I knew the bees were there, but I didn't actually see any until I took the nest to an event for schoolkids at the Napa County Fairground. A bee came out, hung around for a while and then flew away. This was in March when the fruit trees were starting to bloom. About 30 holes were filled in the nest log, each with several bee eggs. A male always hatches first; females follow.
I watched the nest log a lot over the next few weeks. The bees had hardly emerged when they began building new nests. Now, once again, 30 holes are filled and the eggs should hatch next spring.
Bumblebees have been present in my garden for several years. They love my Salvia macrophylla ‘Hot Lips', which is native to Mexico. Sometimes the plant is covered with bees, mostly bumblebees.
Last spring I learned about the teddy bear bee (Xylocopa varipuncta), a common name for the male Valley carpenter bee. I was working in my garden when a big yellow bee approached me and buzzed slowly back and forth in front of me. He was an attractive bee, so I went inside to research him and identify who was visiting me. I learned that the males have no stinger and can be an inch long. He was definitely the biggest bee I have ever seen.
If you want to draw these bees to your garden, plant California native plants. The native bees and plants developed together. Honeybees were imported to this country because they produce honey. However, they have had many health problems over the past years.
Scientists are studying how native bees might play a bigger role in pollinating crops. About 100 food crops need pollination annually to produce fruit.
I even find bees in my garden in winter. I have a clematis that blooms in December and January. When I go out in the cool of the day, I find bees sleeping in the blooms. I never linger long enough to identify which type of bees they are, but I like knowing they are still flying.
Among the other native bees are digger bees and sweat bees. Some native bees are as tiny as gnats. Seventy percent of bees nest in the ground and the rest in wood holes.
At one time, I had many paper wasps building nests in my garden. They were docile around me, and they did gather insects for their nests. One winter a queen wasp overwintered on a door in my shed. I would go in periodically to check on her. She had many small wasps gathered around her, but their numbers kept declining so I often wondered if she ate them to get her through the winter. Eventually she was the only one left in the shed.
If you would like to learn more about native bees, you can find many resources online. California Bees and Blooms: A Guide for Gardeners and Naturalists by Gordon W. Frankie, Robbin W. Thorp, Rollin E. Coville, and Barbara Ertter is an excellent reference. You can also consult www.helpabee.org.
Tree Walk: Join U. C. Master Gardeners of Napa County for a free guided tree walk through Fuller Park in Napa on Monday, August 8, from 10 a.m. to 11:30 a.m. Registration is recommended as space is limited. Meet at Fuller Park, corner of Jefferson and Oak Streets. Online registration or call 707-253-4221. Trees to Know in Napa Valley will be available for $15. Cash or check payable to UC Regents. Sorry, we are unable to process credit cards.
Workshop: The U. C. Master Gardeners of Napa County will host a workshop on “Growing Fall and Winter Vegetables” on Saturday, August 13, from 9:30 a.m. to 11:30 a.m., at the University of California Cooperative Extension, 1710 Soscol Avenue, Napa. Discover the joy of harvesting vegetables from your own garden in fall, winter and early spring. Topics will include timing, watering, fertilizing, managing pests and harvesting. On-line registration (credit card only). Mail-in/Walk-in registration (cash or check only).
Master Gardeners are volunteers who help the University of California reach the gardening public with home gardening information. U. C. Master Gardeners of Napa County ( http://ucanr.edu/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.