Garden Calendar for May

Lilacs in Bloom

Lilacs in Bloom

May brings yard and garden activity to a fever pitch, and the Nursery at Reds is fully stocked with all kinds of plants and products for the itchy green thumb. Proceed with caution early on for some activities, however, as the weather can still be uncooperative and winter-like well into the month.

Shrubs and Trees

  • Remove winter protection wraps from young trees; if left in place they create a haven for insects.
  • If you haven't done so already, fertilize trees, evergreens, and shrubs to maintain health and encourage growth. Many turf fertilizers contain high levels of salt, chlorine, and insoluble materials which can damage trees and ornamentals, so be sure to use a fertilizer blend formulated specifically for trees.
  • Remove vertical branches ("water sprouts") and suckers from flowering crab and apple trees.
  • Plant ground covers under shade trees that don't allow enough sunlight to sustain grass. Periwinkle, Pachysandra, and English Ivy are three ground cover plants that grow well in shade.

Lawn Care

  • Early May is a good time for fertilizing lawns. Choose a fertilizer with controlled-release or slow-release nitrogen.
  • Weed and feed mixes take a shotgun approach to weed control. The herbicide is broadcast with fertilizer with the hopes that enough weed killer is present where the weeds are to kill them. These products are a good approach where weeds are scattered here and there throughout the lawn, but it's best to spot treat, too, when you have bad infestations in localized areas, Just allow the proper time interval to pass between applying the weed and feed to the whole lawn and treating the problem spot.
  • Consider core aerating your lawn if your lawn was sodded or has developed a heavy thatch layer. Aeration will help alleviate the symptoms of necrotic ring spot. Unfortunately, while May is a good time to aerate, it is often difficult to time. If you try to aerate when the soil is too wet, the aerator will become clogged and you may actually compact your lawn in the process. For that reason, it is generally considered easier to aerate in September.
  • Never let your lawn grow so high that you need to cut off more than one-third of the height of the grass blade at a time. Such extreme leaf removal stops the flow of food to the roots, weakens the plants, and opens the lawn to diseases. If necessary, raise the mower cutting height, mow, then two days later lower the cutting height and mow again.

Perennials, Annuals, and Bulbs

  • Finish preparation of planting beds, but use patience when putting out annual flowers. It's best to wait until mid-month rather than take a risk of a late frost.
  • Lightly sidedress early bloomers, including spring bulbs, with a perennial fertilizer, being careful to avoid the center or crown of the plant. May is also the time to start feeding your roses.
  • Plant gladioli and dahlias about two weeks before the anticipated last frost. By the time they emerge from the soil, the frost danger will be past.
  • If you didn't feed your peonies last fall, now would be a good time. Use a shovel full of composted manure and a cup of bone meal per plant, cultivated in around the drip line of the plant. Keep composted manures away from the peony plants to avoid Botrytis blight.
  • Once the danger of frost has passed, bedding plants are the answer to a gardener's prayer for faster color and growth. Select short, compact plants, preferably ones that have not yet begun to bloom. If necessary, pinch or shear off flowers and buds before planting to give the roots an opportunity to become well established. At this time, the "energy" a plant spends on producing blooms takes away from the "energy" it needs to establish itself in your garden! Here are a few tips for working with bedding plants:
    • Plants should pop out easily when the pack is turned on its side. If they don't, gently squeeze the bottom of the cell to loosen the roots, then try again. Handle plants carefully, holding them by the ball of soil and roots.
    • Prepare the planting bed by loosening the soil to a depth of six to eight inches.
    • Check the plant label for recommended spacing, and then dig each hole slightly larger than the root ball. Add two inches of compost or composted manure, and mix in well. Gently place the plant in the hole, filling in with garden soil and tamping securely into place.
    • Drench the soil around the plants, watering slowly, deeply, and evenly, and fertilize according label directions.
    • Mulch to retain moisture and keep down weeds.
  • Protect your annuals! Anytime the forecast calls for temperatures below 40°F, we reccommend you bring your container plants and hanging baskets indoors.

Fruits and Vegetables

  • The rims from peat pots act as a wick to draw moisture away from plant roots, so remember to break them off before transplanting.
  • Schedule vegetable planting with caution. By the middle of the month vegetables such as snap beans, beets, and sweet corn can be planted, but wait until Memorial Day to set out warm crops such as lima beans, cucumbers, eggplant, peppers, sweet potatoes, pumpkins, squash, tomatoes, and watermelon.
  • Plant corn in a block of at least three rows, as it is wind pollinated.
  • For best growth and yield, side dress your vegetable garden every couple of weeks, starting about a month after transplanting or seeding.

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