The Digging Fork -- Mar-apr 2007

The Digging Fork A Davis Garden Newsletter March – April 2007 March Planting see Plant notes

Seeding see Plant notes

Cool season vegetables: seed potatoes Warm season annuals: many Perennials: almost everything, but especially citrus trees and frost tender plants Warm season bulbs: many Cool season vegetables: beets, carrots, leeks, Swiss chard, parsnips, green onions, radishes Warm season vegetables: beans (dry, snap) Warm season annuals: many

April Warm season vegetables: best to wait until mid April to early May to plant:

basil, eggplant, peppers, tomatillo, tomato Perennials: most Warm season bulbs: many Warm season annuals: many Warm season vegetables best to wait until mid April to plant most seeds:

beans (dry, snap, lima), corn (and popcorn), cucumber, gourds, okra, melons, peanuts, summer and winter squash, soybeans, watermelon Warm season annuals: many

Fertilize

Citrus with citrus fertilizer. (Fruit-bearing trees if not fertilized in Feb. Don’t fertilize frost damaged trees) Roses, flowers and lawns when growth starts Fruit trees with 1st irrigation

Pest & Disease Control

Snail, slugs and earwig damage –use baits or traps. Aphids. Can spray off with water and watch for lady beetle & parasitic wasps Citrus and other evergreen shrubs sprayed with horticulture oil to control scale and insects eggs.

Snail, slugs and earwig damage –use baits or traps. Aphids. Can spray off with water and watch for lady beetles & parasitic wasps

Tasks

Prepare beds for planting – don’t dig soils that are too wet. A handful of soil should crumble Divide & replant perennials Prune evergreen shrubs when new growth appears Some frost damaged plants will be ready to prune – watch for new growth Weed control continues

Prepare beds for planting. (see note in March) Divide & replant perennials

Water

May need to start watering. Did you check sprinklers and drip systems?

Weed control continues Prune deciduous shrubs and vines after they flower. Clean up the vegetable and flower beds to make room for warm season plants. More frost damaged plants will be ready to prune – watch for new growth Thin fruit trees, except cherries Water as needed.

Calendar layout thanks to Lyle Wilen

Cast-iron plant with rarely seen red flowers

Garden in early spring. Calendulas, veronica, blue fescue and sedum.

Spring Planting This is a crazy but exciting time of year. The cool season plants are starting to bloom and the garden is changing weekly. For many of us, our thoughts are on getting those tomatoes in. Relax, and enjoy the spring! Warm season plants really do want warm weather which comes to Davis around mid April or even into May, when the air temperatures are consistently in the 70s and soil temperatures are warming. Spring is a good time to plant perennials, especially those that are frost sensitive and should not be planted in the fall. Some warm season annuals are easy to start by seeding directly into the ground. Examples are marigold, cosmos, zinnia and sunflower. Although many of these are also available as transplants, it is cheaper to start them by direct seeding, however bloom can be delayed. One favorite annual that Patricia planted many, many years ago is what her father called knotweed. It has been reseeding each spring since -the seedlings are distinctive with red stems. It is now easy to find seeds for this pink flowered annual, also called kiss-me-over-the-garden-gate. The plant grows tall, to over 6 feet, and the flowers are good for cutting if you remove the leaves. Many bulbs are planted in the spring for summer and fall bloom. These include dahlias, gladiolus, Peruvian daffodils and calla. Peruvian daffodils like sun and will bloom in July with white or light yellow flowers. They are a great cut flower. A great plant for shade is the cast-iron plant. It is grown for the foliage but actually has flowers that were found accidentally when the plant was being dug to share with a friend. The red flowers are only about 2 inches tall and lost in the 2 to 3 foot tall leaves. Generally only the dead leaves are removed from this evergreen plant, but one of Patricia’s plants was cut to the ground last fall and the leaves haven’t emerged yet, allowing us to see all the flowers. Cast-iron plant is wonderful when planted with spider plant, sword fern and pig squeak for contrasting foliage in shade.

penetrate. A digging fork leaves an irregular transition from the dug to undug soil. Rototillers rarely cultivate as deeply as a digging fork and it is easy to pulverize the soil with too many passes. Adding organic matter. Organic matter incorporated into the soil as an amendment will immediately help to keep the clay particles separate. The best organic material to add to soil is humus/compost as it helps to organically bind the clay particles into larger units. As microorganisms decompose organic material into humus/compost, they use nitrogen. Adding organic materials that still need to decompose will result in a short term loss of available nitrogen for the plants, requiring the addition of supplemental nitrogen. Organic materials applied as a mulch on top of the soil will also improve the soil structure but at a slower rate. Mulch has many other benefits that will be discussed in the next newsletter. The organic component of the soil is constantly changing and will decrease over time if organic materials are not added on a regular basis. Sand is NOT a good soil amendment to add to clay soils as prohibitively large quantities (45% by volume) would be needed to improve soil structure. Sand added in smaller quantities reacts with the clay particles to produce something similar to cement. Davis soils are somewhat alkaline. This, together with our water that is high in calcium, makes growing acid loving plants such as camellias, azaleas, and hydrangeas difficult. Gardening friends in neighboring cities have no problem growing these plants. The addition of organic matter and soil sulfur will help to make our soil a bit more acid, but acid loving plants are still challenging to grow.

Building and Maintaining Healthy Soil Davis soil has a bad reputation. When our clay soil is wet, it sticks to shoes and can’t be easily worked -when dry, it is very hard and cracks form on the surface. Unfortunately, there is a very small window when the soil is neither too wet or too dry and is perfect for digging and planting. The good news is that clay soils are full of nutrients plants need and with a little effort, the structure of clay soil can be improved. Since the clay particles are so very, very tiny, they are easily compacted and can hold onto water. This creates little room for the air that plant roots need. The goal is to restructure the clay particles into larger aggregates or granules, allowing water to drain faster and providing space for air. Cultivation and the addition of organic matter are two ways to improve clay soil. Cultivation. Digging clay soils when too wet will undo all the efforts of aggregating the soil. Soil is ready to dig when a handful will crumble when squeezed together and not form a clay ball. A digging fork (not a pitch fork) is our preferred digging tool. If the soil is very compacted, it is important to insert the tines only a couple inches into the soil and rock the handle toward your body. Then insert the tines a bit deeper and repeat until the soil is loosened about a foot deep. Don’t turn the soil over, as there is no need and it is more work. Breaking up clods some is fine but usually not necessary of you later mulch the bed. Gently dig between plants already in the bed. A shovel could be used to cultivate, but it can leave sheared, compacted areas that are difficult for roots to --continued in next column –

More local classes and workshops Woodland Community College Weekend classes: Gardening: Controlling Yard Pests Gardening: Irrigation Gardening: The Organic Way

Classes meet Friday evenings and Saturday mornings. For information & cost: www.yccd.edu or (530) 661-5700

Digging with a digging fork

Master Gardener Workshops:

Marlene & Patricia’s Garden Workshops

Spring into Gardening Fair at Woodland College March 3 Registration begins at 8 am $5 fee Gardening with Children (free) April 15, 1–2:30 pm Gardening with Herbs (free) April 28 1-2:30 pm

Workshops are held in Patricia’s one acre country garden in Davis. There is time to explore and ask lots of questions. Cost of workshop $25. If you bring a friend or spouse the cost is $20 per person. Class size is limited.

Information for fair and workshop (530) 666-8143

UCD Project Compost Workshops:

Vegetables for Warm Season

Backyard Composting March 31, 11 am–1 pm

Saturday, March 10 11:00 am -2:30 pm Back up date due to rain – Saturday, March 17

For information: (530) 754-8227 [email protected]

Spring Garden Cleanup and Planting Saturday, May 19

March 9-10 March 30-31 April 6-7

Davis Backyard and Worm Composting Classes:

11:00 am – 2:30 pm

Free classes at the Community Gardens on Fifth St. March 3 or April 23 1 – 2 pm

Problems, problems, problems!!

(weeds, pests, fertilizer, plant spacing, timing of planting, healthy soil, water, etc.)

To register -- call Public Works Dept. 757-5686

June – date TBA

Davis Central Park Gardens

To register for workshops:

The gardens are being renovated! See the web site for plans, workshops and events. http://www.centralparkgardens.org

Call Marlene (530) 400-7010 or Patricia (530) 753-0607 or email [email protected]

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Plant notes! Here is more information about some plants mentioned in this newsletter.

Perennials (and biennials): blue fescue Festuca glauca ( Syn. F. cinerea) Pictured is ‘Elijah Blue’, a grass that grows only 8” high

cast-iron plant Aspidistra elatior Grows in deep shade. pig squeak Bergenia Shade. Leaves do squeal like pig when rubbed. sedum (stonecrop) Sedum Succulent. Many varieties available. spider plant Chlorophytum comosum Dry or moist shade. sword fern Nephrolepis cordifolia Shade. May die to ground in cold winters but resprouts in spring.

veronica (or speedwell) Veronica umbrosa ‘Georgia Blue’ Ground cover with blue flowers in early spring. Plant with daffodils.

Warm season annuals:

Striking yellow aphids

Parasitized aphids -- the hole is where parasitic wasp emerged Photos by Jeff Austin (thanks for sharing!)

basil Ocimum basilicum Culinary herb. Bait new plants and seedlings – snails and slugs love them.

cosmos Cosmos bipinnatus Sun. Easily direct seeded, cut flower. knotweed, kiss-me-over-the-garden-gate Polygonum orientale Sun, and grows over 6 feet tall. Reseeds. Sorry, no

Pests

photo – check the web.

Spring brings succulent new growth. But along with this new growth comes the pests that feast on it. Two of the most problematic are snail and slugs which can chomp down new seedlings before a gardener can even witness their emergence!! One control is to simply pick them off as the sun rises or sets. Snails and slugs however, can be controlled in a relatively safe way by using iron phosphate commonly found under the brand name ‘Sluggo’. Unlike the metaldehydes, iron phosphate is safe to use around wildlife. However, don’t expect to find the empty shells of the snails the next morning. Once they consume the iron phosphate, they slime away to die somewhere else. It is satisfying to see numerous empty snail shells during garden clean-up! Some gardeners see aphids on their plants and assume if action is not taken their garden will be ruined. Before reaching for chemicals, assess the situation. Look for natural enemies such as parasitic wasps and lady beetles and let them take care of the problem. Parasitic wasps lay their eggs in the aphids. The larva hatches, eating the insides of the aphids, killing them. The adult wasp later emerges from the mummy. Aphids in small numbers are fine and no control measures are needed. If numbers are high, try simply wiping or spraying them off with water. If numbers are overwhelming, a horticulture soap spray can be used. Do not use the sprays in the heat of the day as burning of foliage can occur. Earwigs can mimic snail and slug damage, but slime trails will not be there. To control or determine if earwigs are the culprit, moisten some newspaper, roll it up and place overnight in the garden. In the morning, if earwigs are present, they should have congregated in the newspaper. Simply throw away the newspaper and repeat until numbers decrease. Another method for attracting earwigs is to use shallow cans filled with water and a layer of fish oil on top. Vegetable oil with a bit of bacon grease works too. See Pest Notes www.ipm.ucdavis.edu

marigold

Tagetes Tall varieties are especially good for cutting. ‘Crackerjack’ is an easy to find variety. sunflowers Helianthus annuus Can start direct seeding in March. Variety ‘Pan’ is a favorite, 5 ft. tall plant has numerous, small golden flowers with dark centers. zinnia Zinnia Sun. Mildew a problem if plant is overhead watered.

Warm season bulbs: calla Zantedeschia A favorite-- Z. elliottiana is yellow and likes sun!! dahlia Dahlia Watch for emerging leaves and bait or trap snails, slugs and earwigs!

gladiolus (grandiflora)

Gladiolus To extend the bloom and avoid thrips problems in hot weather, plant bulbs every 15 days Jan. to March.

Peruvian daffodil Hymenocallis narcissiflora (Syn. Ismene calathina) Sun. Yellow and white varieties. Will multiply.

Warm season vegetables: corn Plant in blocks rather than rows since wind pollinated, leave suckers as no change in yield. Baby corn is fun to grow in smaller gardens. Patricia usually plants the variety ‘Chires Baby’ which will produce numerous baby ears per plant. Harvest as silk appears to a few days after. If you miss the harvest period, let mature & dry for popcorn. cucumbers Plant on trellis to save space. Lemon cucumbers are mild and easy to grow. eggplant Plant when air temp. above 70 deg F!!! If planted too early, plant may become stressed and never recover, producing low yield. Plants are pretty and can be planted in the flower garden. Heavy fruit can break stems. Eggplants like lots of sun and water. peanuts Fun to grow. Can plant raw supermarket peanuts --shell before planting. The fertilized flower produces a peg that grows downward and penetrates into loose soil where the peanut forms. peppers (sweet and hot types) Support is a good idea as heavy fruit can break stems. Peppers sunburn easily, afternoon shade or shade cloth is best in Davis. soybeans (edamame type) Glycine max Easy to grow – pods harvested in fall. Flowering is daylight sensitive and there are long and short day varieties. The easy to find Lake Valley Seeds ‘Edamame’ variety has done well in Davis.

Cool season vegetables: March is the last chance to plant vegetables that like cool weather.

potatoes Tubers are really swollen underground stems. The more stem underground, the more potatoes produced. Plant seed potatoes in trench and cover stems with soil as they grow. carrots Difficult to germinate seed – must be kept moist. Try covering with wet burlap bag until sprouts visible. Or mix carrot and radish seeds before planting. Radishes germinate quickly providing shade for slower emerging carrots.

Cool season annuals and bulbs: anemone Anemone coronaria Tuber planted in the fall, not now!! calendula (pot marigold) Calendula officinalis Winter flowering plant but it reseeds aggressively!!

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Citrus

Plant sales and events

Spring has arrived and the threat of frost is almost passed so citrus planting and maintenance should be on your to do list. Whether you are planting a mandarin, lemon, grapefruit or an orange tree, the rules are the same. Make sure the spot you choose to plant your citrus gets at least six hours of sunlight. For sweet varieties, this is particularly important for accumulating sugars in the fruit. As this past January has shown, citrus are susceptible to frost so planting against a south wall or along a fence can create a warmer microclimate than being out in the open. Most citrus come grafted, so make sure the graft is planted a few inches higher than the ground surface. Fertilizing young citrus trees is different than fertilizing requirements for fruit-bearing citrus. Trees not producing fruit should be fertilized with a small amount of nitrogen three to four times a year (Feb., Mar., May and Aug.) as recommended by UC farm advisors. Nitrogen is the most important nutrient because it promotes growth of green material. Fruitbearing trees can be fertilized with a slow-release citrus fertilizer in early spring and summer (Feb or Mar. and Aug.) to help with flower and fruit production. If fertilized in the fall, the new growth promoted by this fertilization is susceptible to frost. If trees have been damaged by frost, postpone fertilizing until they recover. Pruning should be done after the threat of frost is past but before new growth occurs. The main reason to prune is for the removal of broken limbs and less producing wood. Note that usually more fruit is produced in lower limbs while less fruit is produced from higher limbs. Frost damage should be removed later after the full affect of damage can be assessed. The more heavily damaged the tree, the later the pruning should be done. Suckers from the rootstock should be removed as they occur. If a plant was killed off entirely during a frost, new growth below the graft is from rootstalk and the tree needs to be replaced. Citrus roots are shallow so be careful when cultivating and irrigating. It is especially important to prevent the roots of young citrus from drying out. Over-watering can be a problem as well, resulting in leaf drop, yellowing of leaves and fungal diseases. With our heavy clay soils it is always important to check the moisture content of the soil before irrigating.

UCD Arboretum Plant Sales March 17 9 am – 1 pm (members only - join at door) April 7, April 21, May 19 9 am – 1 pm (open to public) For information www.arboretum.ucdavis.edu Wildflower Weekend --California Native Plant Society April 21 and 22, 10 am – 4 pm. Free. For information www.SacValleyCNPS.org Pence Garden Tour (College Park area) May 6 12 noon - 5 pm. For information 758-3370

Woodland Rose Tour April 29 12 noon $20 (includes snacks) Rain date May 6 For information 668-0944

Jepson Prairie Preserve Spring Wildflower Tours For information (707) 432-0150

Davis Garden Club Davis Public Library, 4th Monday of month, 7 – 9 pm For information 220-3052 www.davisgardenclub.org

Ornamental cabbage during January frost.

Cut back to new buds.

More gardening tips! Increasing your observation skills will make you a better gardener! There will still be cool season annuals, in flower, being sold in nurseries. These plants were best planted in the fall. Planted now they don’t do much before the warm weather arrives. These plants aren’t annuals!! Don’t pull out snapdragons, stock and ornamental cabbage when finished blooming this spring. Cut them back for future blooms. Ornamental cabbage should be cut back before flowering (look for the new buds on the stem). The leaves will be green during the summer but will color up again in the fall with many new rosettes per plant. Good source for spring planted bulbs: McClure & Zimmerman 1-800-883-6998 www.mzbulb.com

Good source for seeds of flowers and vegetables: Johnny’s Selected Seeds 1-877-564-6697 www.Johnnyseeds.com (knotweed) Seeds of Change 1-888-762-7333 www.seedsofchange.com (organic seeds, ‘Chires’ baby corn)

Newsletter created by: Marlene Simon -- UCD graduate in Horticulture Patricia Carpenter -- Garden Design and Education, with 30 years of Davis gardening experience. The bi-monthly newsletter is free if received by email. If mailed, the cost is $6 per year. To be added to the subscription list or to unsubscribe, contact us at: [email protected] Spring blooming red anemone and veronica ‘Georgia Blue’

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