In Lewis Carroll's Through the Looking-Glass, Alice finds herself in the Garden of Talking Flowers. These flowers are quite outspoken, criticizing Alice's hair, demeanor and general ignorance about their way of life. If my roses could talk, they would tell me how grateful they were for all the rain this spring, and perhaps they would give me a hard time about how grudging I was with that commodity last year.
They would be correct. The goal was to survive, but not necessarily thrive. If your roses are like mine, they are proving their resilience by putting forth a lovely display of flowers right now. But what can we do to keep them healthy and productive for the rest of the season?
First, remember to water your roses during the growing season. This is especially important for roses that bloom repeatedly. Roses that bloom only once a season (usually known as "heritage" or "old garden" roses) do not need a great deal of water once they are established. All other roses need regular watering.
You can use basin watering or drip irrigation. The latter method allows you to water several plants at once. Overhead watering can help wash away aphids and other pests as well spores and mildew. Do it early in the day so the leaves have time to dry. Dampness can encourage fungi. Inspect the plant before watering to make sure you aren't washing off beneficial insects such as ladybugs. Mulching around your roses will keep roots cooler so the plant will need less water.
Fertilize right after each bloom cycle to encourage more flowering. First remove the spent flowers (a practice known as deadheading), then fertilize. Dry fertilizers dug into the ground are effective. Add some compost while you're at it.
If you practice basin watering, you might prefer a liquid fertilizer. Some gardeners spray the leaves directly with a hose-end applicator. Again, do it early and watch for beneficials.
The New Sunset Western Garden Book recommends dehydrated alfalfa as an organic fertilizer because it smells better than fish emulsion. It's also a good way to add nitrogen to the soil.
Even roses that flower only once will benefit from a meal after bloom. They won't flower again, but the nutrients will promote growth in the spring.
As the first bloom fades, you may notice black spots on some rose leaves. Perhaps some leaves have lost color in places or have a powdery white deposit. Black spot, rust and powdery mildew are common rose maladies in Northern California, especially after a wet spring. Rust (Phragmidium mucronatum) is a fungal disease that leaves the top of the leaf discolored, with rust-colored pustules on the underside. Powdery mildew (Podosphaera) presents as a white powdery coating on buds, stems and leaves.
At the first sign of any of these problems, remove affected leaves, stems, buds and flowers. Pick up any fallen leaves or flowers to prevent the disease from spreading. Put the affected foliage in your yard-waste bin--not your compost bin--for the same reason. Many of my own rose woes can be traced to inadequate cleanup.
Both the University of California's "Rose Pest Notes" and the Sunset book recommend spraying to combat these pathogens. Spray the leaves, not the flowers. For rust, use a garlic-based or copper soap fungicide. For powdery mildew, use Neem oil or other horticultural oils, a baking-soda mixture, a copper soap fungicide or sulfur.
Black spot (Diplocarbon rosae) produces black marks with irregular edges on the top of the leaf. Often the leaf turns yellow. Horticultural oils can help reduce black spot. Oils can coat insects—including bees—so apply them at the end of the day when the insects have retired for the evening.
Roses are exuberantly beautiful, and to me that is reason enough to nurture them through their ailments. Give them a little care and they will reward you with color and fragrance well into autumn.
Workshop: Napa County Master Gardeners will hold a workshop on “Rose Care” on Saturday, June 4, from 10 a.m. to noon, at University of California Cooperative Extension, 1710 Soscol Avenue, Napa. Join the discussion about spring and early summer rose care, issues and solutions. Learn about integrated pest management for common pests and diseases and how to keep your roses healthy during our current drought. 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.
One of my favorite houseplants at this time of year is holiday cactus. During November and December, these cacti are covered with long tubular blooms. Over the years, I have collected several plants, each with different colored blossoms, including white, pale pink, hot pink, red and salmon.
While I used to think that all of these plants were Christmas cacti, I recently learned that two types of holiday cacti bloom during November and December. The one that most stores sell is Schlumbergera truncate, the so-called Thanksgiving cactus that blooms around that holiday. The second type is Schlumbergerabridgesii, which blooms about one month later. That one is the true Christmas cactus.
The Thanksgiving cactus has flattened stem segments with saw tooth projections along the margins; the Christmas cactus has more rounded margins. In addition, the anthers of the Thanksgiving cactus are yellow, while the anthers on the Christmas cactus are purplish-brown.
These cacti are native to South America, growing in tropical jungles at altitudes ranging from 3,000 to 5,000 feet. They are epiphytes, meaning that they grow on objects or other plants. They obtain water and nutrients from the humid air around them instead of from the soil. When grown indoors, these cacti need bright but filtered light, so place them near a south-facing window. In warmer months, they can live outside in a sheltered shady place.
While these plants are easy to grow, it is sometimes a challenge to get them to bloom for the holidays. There are a few tricks to encouraging bloom.
Pinch back the stems in early June to encourage branching and more terminals for flowers. At the end of September, remove any end segments that are either damaged or less than a half-inch long. Flower buds will only form on undamaged, mature stem segments.
Holiday cacti set their flower buds when the days turn shorter and cooler. To create optimum blooming conditions, provide cool nighttime temperatures (50°F to 55°F) and 12 to 14 hours of darkness starting in mid-September. Street lights, car lights or indoor lighting can disrupt the required dark period, so place cacti where constant darkness is guaranteed. Reduce watering as growth slows. When flower buds appear, gradually increase watering and provide temperatures between 60°F and 65°F. Feed every other week during the bloom period with a fertilizer intended for houseplants.
While the plants are blooming, keep them away from drafty spots and heating or air conditioning vents. After blooming, the plants appreciate a rest period of six to eight weeks. Keep them cool (around 55°F) and water lightly until new spring growth appears. During the growing season,feed monthly with houseplant fertilizer diluted to half strength. Stop fertilizing in late summer to encourage fall flowering.
Holiday cacti like to be pot bound. Repot them about every three years in the spring. Choose a fast-draining mix containing 60 to 80 percent potting soil and 20 to 40 percent perlite. Allow the soil mixture to dry out partially before watering so air can circulate around the roots.
Propagate the cacti by taking cuttings in May or June. Select stems with three to five segments. Let cuttings dry in the shade for at least one day. Fill a clean four- to six-inch container with fresh potting soil. Insert three to five cuttings one inch deep into moistened soil.
Cover the plants and container with a clear plastic bag or other translucent material to create a mini greenhouse. Support the plastic so that it does not touch the cuttings. A clean, clear plastic soda bottle with the bottom removed works great as a covering. Place the covered container in bright, indirect light. In three to eight weeks, roots will form and you can remove the covering.
If your cactus isn't blooming by Christmas, all is not lost. Give it the daily darkness treatment for six to eight weeks, and you should have a flowering plant by early spring.
Workshop: U. C. Master Gardeners of Napa County will host a workshop on “Rose Pruning and Maintenance” on Saturday, January 9, from 10 a.m. to noon, at the University of California Cooperative Extension office, 1710 Soscol Avenue, Napa.This workshop will feature demonstrations of proper pruning techniques. Master Gardeners will discuss types of roses, common rose diseases and routine maintenance On-line registration (credit card only) coming soon. Mail-in registration (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.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.
In our climate, fruit trees do need to be watered periodically to stay healthy. A fruit tree's water needs depend on its size, day length and the weather (air temperature, humidity and wind). Under-watering will reduce fruit size and tree growth. With extreme water stress, fruit can sunburn and may shrivel and drop, and the tree may lose its leaves.
Can your fruit trees survive with less water? Yes, they can. In a year with normal rainfall, the soil at the beginning of May is holding as much water as it can. Ideally, you would observe the surrounding hills and start watering when the grass turns brown—a sign that the top six inches or so of soil have dried out. At that point, young trees need to be watered every 10 days to 2 weeks. Established trees only need water every three to four weeks from June through August. This infrequent watering encourages deeper roots, which makes more water available to the tree.
Trees that are one to two years old need just one to two gallons of water per day (applied 15 to 30 gallons at a time). A mature tree can use 50 gallons on a hot summer day. It might need 1,000 gallons every four weeks to replenish the water it takes out of the soil.
Make sure you water slowly enough so that all of the water is absorbed. Younger trees are more susceptible to water stress than established trees. And although you may have heard that citrus trees are drought resistant, they have shallow roots and are actually among the least drought-resistant fruit trees.
So what actions should you take in a drought year?
Water early. In a drought year, the root zone will dry out earlier so you have to start watering earlier. Adequate irrigation early in the season is more important than water later. Trees grow more slowly later in the season, and most trees will have already borne fruit. They may lose their leaves and set few flower buds, but they will survive. In extreme drought, deep watering once or twice in the spring and early summer will likely keep trees alive. However, these trees may not bear fruit.
Mulch your soil. Keep soil moisture from evaporating by applying a generous layer of mulch. Mulching also minimizes weeds that compete with your trees for water. Organic mulch will increase soil fertility and the soil's ability to hold water. Apply mulch to moist soil. If your garden has already dried out quite a bit, water first, then mulch.
Keep your trees small. The smaller the tree, the less water it will need. Home gardeners rarely need all the fruit that a mature standard or semi-dwarf tree produces. Smaller trees are also easier to manage. Thin stone fruits, apples and pears when they have the diameter of a quarter, keeping only about half as many fruits as you normally would. Fewer fruits require less water, and you have a better chance of getting good quality.
Prune hard. During the dormant season, cut back your fruit trees by about one-third. Then prune during the growing season to minimize growth. The goal is to limit the number of leaves the tree is trying to support. You will sacrifice fruit, but your tree will survive on less water. When you prune, paint the newly exposed limbs and trunk area with a mix of equal parts light-colored interior latex paint and water.
Water the right trees. Among common fruit and nut trees, almonds, figs and olives are the most drought-tolerant. Nectarines, peaches and citrus are the least tolerant.
Grow healthy soil. Keep adding amendments. The more organic matter in your soil, the more water it will hold. Healthy soil holds up to five times as much water as depleted soil.
Workshop: Napa County Master Gardeners will hold a workshop on “Let's Talk Rose Care for Spring and Early Summer” on Saturday, May 23, from 10 a.m. to noon. Join in the discussion about spring and early summer rose care, issues and solutions. We will talk about integrated management for common pests and diseases and how to keep roses healthy even during our current drought and water restrictions. Location: University of California Cooperative Extension, 1710 Soscol Avenue, Napa. Online 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.