Gardening Tips for the Month of May


Ornamental Pepper 'Black Pearl' shows off against a chartreuse coleus

Garden centers are overflowing with new and fresh plants for the garden.  Early May is a great time for setting out new annuals to take the place of winter color.  And the number types and varieties of colorful perennials available for adding color and interest to the garden increases every year.

In the flower garden, you have time to directly sow into the soil seeds of sunflower, zinnia, morning glory, portulaca, marigold, cosmos, periwinkles, and ornamental gourds. Achimenes, cannas, dahlias, and other summer-flowering bulbs and corms can also be planted in May.

For shaded areas, try caladiums, impatiens, New Guinea impatiens, coleus, begonias, and annual salvia. Flowering tobacco (Nicotiana) is a great fragrant annual for partial shade.

There are so many perennial options for sunny spots. A few choices include Shasta daisy, Artemisia ‘Powis Castle’, garden mums, coreopsis, mallows, all kinds of salvias, coneflowers, blackeyed Susans (Rudbeckia), and summer phlox. Perennials for shaded spots include hosta, columbine, farfugium, toad lily, and all kinds of ferns.

Pinch back growth of newly planted annual and perennial plants. This results in shorter, compact plants with more flowers.

Be sure your garden, flowers and shrubs have a layer of mulch over the soil surface to reduce weed growth and to conserve water. Pine needles, pine bark, hardwood chipper mulch and shredded leaves are examples of mulching materials.

Prune, if needed, spring-flowering shrubs soon after flowering. Keep the natural shape of the plant in mind as you prune, and avoid excessive cutting except where necessary to control size.

Resist the urge to cut back the lankly green leaves of your spring bulbs. Allow the foliage mature and yellow before removing. Those leaves are making food to help produce next year’s flowers.

Lawn Care. Water lawns only as needed. Certainly grass does not need watering every day or every other day, even in sandy soils! Monitor weekly rainfall amounts this year. An inch of rain is sufficient to take care of your lawn’s water needs per week. Most lawns can easily get by with twice per week watering. Don’t let the drought of 2010-11 become a distant memory. Conserving water is the wise thing to do.

May is an ideal time to plant a new lawn, or repair spots that died over winter. St. Augustine, Bermuda, zoysia and centipede can all be established quickly with the warmer spring temperatures, yet it is not so hot that watering becomes a great chore.

May is the month to fertilize centipede and zoysia lawns. If you have not yet fertilized Bermuda or St. Augustine, they also can be fertilized now. For longer lasting results, and to avoid promoting lush, disease-prone turf, use a fertilizer with a high percentage of the nitrogen in a slow release form. The benefit to the lawn far outweighs the few cents more it may cost. In the absence of a soil test, use a 3-1-2 or 4-1-2 ratio fertilizer.

Once tomatoes and peppers begin to set fruit, lightly apply nitrogen fertilizer (called side dressing) every 7 to 14 days. This supplemental feeding keeps the plants vigorous and growing, allowing them to set and mature the maximum amount of fruit. Mulch around tomatoes to maintain even soil moisture – this will help to reduce blossom end rot problems.

Check azaleas for lace bugs. These are small, slow moving, black insects with clear, lacy wings that feed on the underside of the leaves, leaving shiny black specks of droppings. Damage to the leaves, which look stippled or bleached, is usually worse on stressed azaleas and those receiving a lot of hot, direct sun.

Aphids (sometimes called plant lice) are common pests on many types of plants, both vegetable and ornamental. While a couple of aphids are no big deal, they multiply faster than rabbits, and can quickly cause deformed and stunted new growth. Blast them off with a strong stream of water, or use an insecticidal soap or pyrethrin as low toxicity options.

Rose blackspot fungus may have been a problem earlier this spring due to the rainy weather, but may have tapered off due to the drier weather. However if the rose leaves are regularly wetted by your sprinkler system, blackspot will continue to be a problem. Keep the foliage dry, and treat with a fungicide at first signs of rose blackspot.  If a rainy weather pattern returns, be assured blackspot will also.

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