April 2013 Gardening To-Do List: Zone 9

Susan Wells
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USDA Plant Hardiness Zones

As gardeners, our least favorite job is dealing with pests. Increasing the biodiversity of our landscape is an excellent and organic defense against many pests. Consider adding plants that will attract beneficial insects to the garden. Adding a water element to the garden will also attract birds, many of which feed on problem insects and their larvae. Install a pump and some fish, and mosquitos won’t be a problem. Click on the map at right to find your zone.

Vegetables

You can encourage beneficial insects by adding the following herbs and flowers to the vegetable garden: catnip, caraway, dill, fennel, thyme, yarrow, daisies, coneflower, cosmos, marigold, and zinnias. 

April may be our last month for successfuly planting slicing tomatoes because high temperatures will stop the plants from setting fruit.  Cherry tomatoes, however, will continue to produce delicious veggies during hot weather.

Direct sow seeds this month for warm-season vegetables such as okra, cucumber, watermelon and squash.

Transplant warm-season vegetable seedlings after they have a second or third set of true leaves.

A woman planting flowers. Flowers

Roses will grow year-round when planted in well drained, organically enriched soil, with several hours of daily sunlight. When choosing new roses, look for ones grafted on ‘Rosa fortuniana’ rootstock. Maintain a pruning, feeding and pest control schedule. Feeding should be done monthly, with a balanced food. Roses are not fond of humidity and may require fungal treatment, which helps with black spot. A few tablespoons of Epsom salts per rose bush provides magnesium for new cane growth.

Plant alliums (chives, garlic, onions, shallots), parsley, and marigolds near roses.

Increase irrigation for your roses this month, watering deeply twice a week.

Feed irises with a low nitrogen fertilizer to encourage blooms.

Use a liquid food for container-grown plants.

Downy mildew fungus on impatiens can be reduced by irrigating with a drip system or by hand watering on the soil around the plants instead of using a sprinkler.

Trees and shrubs

You can still fertilize shrubs and trees in April. Use a slow release product designed for the plants you are treating.

Symptoms of iron deficiencies can show up as  yellowing foliage on oaks and pines growing in alkaline soil. Treat with chelated iron, as directed by the manufacturer. Also apply garden sulfur to help acidify the soil.

Spray for tree worms and caterpillars in April with a product called Bacillus thuringiensis (Bt). BT contains a live bacteria which lasts on the plant for up to about four days. It infects certain leaf eating caterpillars. BT does not kill bees. As always, spray when there are no winds.

Lawns

Apply broadleaf weed killers in April when the weeds are tender and vulnerable. The mild temperatures make these products easier on the turf.  Use the correct product for the type of lawn being treated.

Brown patch disease may be active in April and should be treated promptly to minimize damage.

Make sure that your mower blades are sharpened or replaced. Mowing will become a regular source of exercise beginning this month. Consider getting a mulching kit to keep from having to rake up the clippings. Let the lawn fertilize itself!

 

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