Sanhedrin Nursery – Garden Blog

• Keep flowers and vegetables in peak condition by giving them a midsummer feeding with a fertilizer that is higher in phosphorus than in nitrogen.

• Check for squash, or “stink”, bugs on squash and pumpkins. Hand-pick grey-brown adults and destroy red egg clusters on the leaves. Use pyrethrins to control heavy infestations.

• Take care of your roses: feed, water, weed, mulch and remove faded blooms regularly. Spray if necessary at first sign of insect or disease problems.

• Sow seeds of perennials like columbine, coreopsis, delphiniums and cone-flowers now for planting in the fall and beautiful blooms next year.

• Impatiens will give you instant color in shady areas and continue blooming right through the fall.

The Trouble with Spider Mites

Spider mites are common pests in the urban landscape and can inflict serious damage to trees, shrubs and flowers. Hot and dry summer weather often encourages the outbreak of spider mites on garden or house plants. Cousins of spiders, spider mites are very small, rarely growing larger than a grain of fine sand. Although small, they can do plenty of damage by sucking nutrients out of plant leaves, and by injecting toxins which curl plant leaves.

The telltale signs of a spider mite infestation are stippled yellow, white or bronze leaves. Sometimes there is a silken webbing on the stems or leaves, and the leaves will appear very dusty and dirty looking. New growth may be distorted, and the plant may be unhealthy in appearance.

To determine if a plant is infested with mites, hold a sheet of white paper underneath an affected leaf and tap it sharply. Minute green, red or yellow specks the size of pepper grains will drop to the paper and begin to move around.

The two-spotted spider mite is one of the ‘warm season’ mites. This pest attacks over 180 host plants including field crops, ornamental plants, house plants and weeds. The females overwinter in the soil or on host plants. They become active in April and May when they seek out the undersides of leaves on suitable hosts. Each female may lay over 100 eggs.

European red mites attacks deciduous trees and shrubs. They are especially common on fruit trees and flowering trees such as crabapples, flowering cherries, pears, plums and hawthorn trees.

Spider mites can be controlled in different ways. They are attracted to dusty leaves, so spraying the undersides of the leaves with a strong blast of water twice a week will help control them. Add some insecticidal soap to the water for even more effective control. Horticultural oil and Neem oil are safe to spray on most plants and they will control spider mites very well.

Oils and insecticidal soap are contact insecticides that kill certain insects and mites by intervening physically, rather than chemically, with their respiratory processes. They affect pests that are present when the spraying takes place, but have little or no residual effect. Under optimum conditions, spider mites can complete their development from egg to adult in less than one week. Populations increase rapidly in warm weather and cause extensive plant damage in a very short time. So several applications 7 to 10 days apart will be necessary. Be sure to saturate the undersides of the leaves.

As with all insect problems, plants which are under
stress of some kind are more susceptible to insect attack. Make sure affected plants are receiving proper sun or shade exposure and the right amount of water. Keep your plants healthy and you will have fewer insect problems.

• There’s still time to plant summer vegetables: tomatoes, peppers, zucchini, cucumbers and corn will bear for you if you plant them now.

• It’s time to set out Brussels sprouts for fall harvest.

• Stake or cage tomato plants before they get any larger.

• Feed rhododendrons, azaleas and camellias with an acid plant food to encourage lush growth. Pinch or prune to promote full, dense growth.

• Fertilize container plants every 10 to 14 days with a liquid fertilizer. Pinch off faded blossoms and they will keep blooming all summer for you.

Secrets of Companion Planting

The practice of mixing flowers and herbs into the vegetable garden or around certain shrubs to attract beneficial insects and repel harmful ones is known as companion planting. Hundreds of examples of plant companions are recorded in garden folklore, and scientific studies have supported many of these.

There are many varieties of herbs, flowers and vegetables that can be used for companion plants. Certain plants act as “trap crops” that draw pest insects away from other plants. Nasturtiums are used this way to attract aphids which seem to prefer them to other crops. Planting a ring of them around apple trees limits woolly aphid damage to the trees (although the nasturtiums won’t look too great).

“Nurse plants” provide breeding grounds for beneficial insects. Herbs such as fennel, dill, anise and coriander are members of the carrot family that produce broad, flat clusters of small flowers that attract beneficials. Grow these plants near your vegetables to keep parasitic wasps nearby. Sunflowers, zinnias and asters also attract helpful insects.

Cucumber beetles, which look like green lady bugs, are a common pest in the vegetable garden. You can lure them away from other plants by planting radishes or nasturtiums nearby. Nasturtiums also deter whiteflies and squash bugs.

Radishes will lure leafminers away from spinach. The damage the leafminers do to radish leaves does not stop the radish roots from growing and being edible, a win-win situation.

Flea beetles are tiny black insects that riddle eggplant leaves with holes. Catnip nearby will deter these creatures. It will also reduce aphids on pepper plants. Keep the catnip in a pot, though, because it can grow out of control in the garden.

Sweet basil is known to repel aphids, mosquitoes and flies. Planted near tomatoes, it is said to help them overcome both insects and diseases and also improves their growth and flavor.

Garlic grown in a circle around fruit trees is good protection against borers. It also deters aphids, weevils and spider mites. It is beneficial when planted around rose bushes for these reasons. Plant near cabbage to repel the cabbage moth and resultant caterpillar damage.

Rosemary deters cabbage moth, bean beetles and carrot flies, so plant some around your vegetable garden.

Marigolds are known for their ability to suppress nematodes. However, we do not have soil nematodes in this area of California. French marigolds help to deter whiteflies when planted around tomatoes and can be useful in the greenhouse for the same purpose. Marigolds may help repel flea beetles from eggplants. For best results plant marigolds that are tall and strongly scented, with the eggplants.

There are many other interesting possibilities. So fill your garden with flowers and herbs and reap their protective benefits as well as their beauty and fragrance.

• Azaleas, camellias and rhododendrons can be pruned now without sacrificing next years bloom. Ask at your nursery if you need help.

• When you finish cutting asparagus, feed the bed with good, rich compost that will also act as a mulch this summer.

• Cover cherry trees with bird netting to protect your crop.

• Finish planting the summer vegetable garden. Seeds of early corn, and beans can go directly in the soil and plants of tomatoes, peppers, eggplant, melons, squash, cucumbers and basil can be set out.

• Red, white and blue petunias or combinations of these with lobelia, geraniums, impatiens and salvia will make a nice display for the Fourth of July.

Tough, Colorful Rockroses

Well-known for their showy spring flowers, rockroses are sun-loving, fast-growing, drought-resistant shrubs that are tolerant of poor, dry soil. They are ideal plants for informal plantings, rocky hillsides or along country driveways.

Since rockroses grow wide, they are at their best where they are not confined to small areas. Use them on hot dry banks, tumbling over rocks, or in a planting of drought resistant shrubs. Given plenty of room, they are beautiful, picturesque shrubs.

Rockroses, or Cistus, are Mediterranean natives that have a long flowering season in late spring. Scattered flowers begin to appear in April; by the end of May the plants are covered with large petaled single flowers; then the blooms taper off through June.

The flowers drop their petals when they fade, so they don’t leave brown, dead flowers on the plant.

Rockrose flowers come in white, pink and lavender-rose, a very striking color. Some plants will grow only thirty inches tall while others reach four to five feet with little effort. Another genus, Halimium, are called yellow rockroses, and they have showy flowers as well.

It is important to choose a variety which will fit the site chosen as rockroses resent severe pruning. Prune only to protect a path from encroachment or to eliminate dead wood or occasional lopsided growth.

Rockroses keep their leaves throughout the year, and are effective at preventing erosion on banks and suppressing weeds underneath them. They are drought tolerant, thrive in rocky soil, and are generally deer-resistant. They also make a pleasant background for flowering bulbs.

There are two requirements for growing rockroses: good drainage and very little summer water. They will often appear at first to respond to frequent irrigation, but the excess water greatly increases the chance of die-back, induces lanky growth and shortens the life of the plants. Plants grown in more natural settings may live for 20 years or more.

Plant rockroses in full sun and add a little lime at planting time. Irrigate deeply and infrequently for the first season. By the second year, most plants can survive without water.

These are truly carefree plants that will delight you every spring with their showy flowers.