May Garden Tips

May Tips

May is one of the busiest months for the avid gardener.  Much planning and planting occurs this month.  Below are some tips that one can do for this month.  The average last frost date for this are is 4/10-4/21.  So, we should be safe for planting many of the annuals and perennials hardy here.  Time to have fun!

Indoor Plants

  • Adding fertilizer to a dry root ball burns the roots, damaging or killing the plant.  So water dry houseplants before fertilizing and NEVER fertilize wilted plants.
  • Once established on a houseplant, powdery mildew is very difficult to eradicate.  If there are only a few spots (gray or white, fuzzy looking), pick off and destroy the affected leaves.  If the problem is more serious, it's best to get rid of the plant before the fungus spreads to other plants.  Powdery mildew is caused by stale, moist air and too much water.  Provide better ventilation or use a small fan to circulate the air.  Cut down on watering.
  • Divide indoor plants when new growth starts in spring.  Root cuttings during spring and summer when the plant is actively growing.
  • Vacation hint:  Sink houseplants, pots and all, in the soil in a shady area of the garden.  Mulch to reduce the need for frequent watering.
  • House plants in containers without drainage holes are poor candidates for outside.  A rainstorm may drown and rot them.  All plants perform better in containers with drainage.
  • House plants may be moved outside when the nighttime temperatures are above 50 degrees F.  Start by putting them in a well-shaded location and progressing to increasingly lighted areas.

Lawns and Landscaping

  • You may ​now aerate, feed and over-seed those bald patches.
  • Now is a good time to add a high dose of nitrogen to warm season grasses.  Better yet, lay down about an inch of compost.
  • Make sure you add at least 1 inch of water per week if it doesn't rain.
  • When grass reaches 3 1/2 to 4 inches, cut only the top 1 inch with your sharp mower blade and leave the clippings on the lawn for nourishment and to help prevent weeds.
  • Now is the time to get a hold of weeds before they get established.
  • If you use sprays, be sure to choose a warm day without wind.
  • Take your time and remove weeds by hand if possible, especially the flowers.  There will be much less work later.
  • Do not put your weeds in a compost pile unless it reaches high temperatures.
  • Reduce the slug population by setting out stale beer in shallow saucers, or remove them by hand.  Your garden will thank you later.
  • Keep a diary of everything you have planted, or even make a landscape map.
  • Keep areas available to plant late summer and fall bloomers for an ever-blooming landscape.
  • Plan areas for new gardens for next year and start preparing the soil so that they will be fertile for planting at that time.
  • Plan spots for your deck or patio for that Memorial Day party and later events.  Set out container plants to create a variety of colors.
  • When you visit botanical gardens and arboretums, take your camera and note pad with you.  Plan now for changes you will make in your landscape.

Perennials, Annuals and Bulbs

  • Plant hardy annuals such as petunia, dianthus, snapdragon and pansy as well as most summer flowering annuals.
  • Make hanging baskets of fuchsia, geranium and impatiens.
  • Plant caladiums and tuberous begonias in shady spots.
  • Packs of seedlings may be set out to harden them off before transplanting.
  • When you begin to plant your herb garden, don't forget to set out enough for the butterflies.
  • Use a liquid fertilizer on established annuals.
  • Start planting bulbs of dahlia, lily and gladiola.  Glads may be planted every week from now till early July for continuous displays and cuttings.
  • Remove fading flowers from tulips and daffodils and give them a dose of fertilizer.  Leave their leaves to help produce bulbs for next year.  Some gardeners "braid" or tie the leaves together to keep their gardens looking tidy.
  • Use a rose fertilizer or an all-purpose garden fertilizer on roses, perennials and deciduous and annual trees and shrubs.  Water thoroughly.
  • When your old friends start poking through, give them a light dose of fertilizer.
  • Prune early blooming shrubs after the flowers fade and fall off.  Then fertilize and mulch.

Trees, Shrubs and Groundcovers

  • Prune out limbs containing tent caterpillars, especially on crabapple and fruit trees, and destroy the limbs.
  • Plant balled-and-burlapped or container trees, shrubs, and vines.  Remember to remove the burlap.
  • Prune frost-sensitive fruit trees.
  • Plant groundcovers under shade trees that do not allow enough sunlight to grow grass.  Vinca minor are groundcover plants that grow well in shade.
  • Mulch around newly planted trees and shrubs.  This practice reduces weeds, controls fluctuations in soil temperature, retains moisture, prevents damage from lawn mowers and looks attractive.
  • Remove the wilting seed heads from Rhododendrons and azaleas, so that the plants energy can go to foliage growth and next years flowers, rather than seeds.
  • Early flowering deciduous shrubs such as Forsythias, Weigela, and Spiraea should be pruned back when they have finished blooming.  Cut back a third of the oldest canes to ground level, then cut back one third of the remaining branches by one third of their height.
  • Work lime in the soil around your hydrangeas to produce pink flowers or aluminum sulfate for blue.
  • Remove any sucker growth from fruit trees as soon as they appear.
  • Use an all-purpose garden fertilizer (10-10-10) to feed roses, deciduous shrubs and trees.  Be sure to water the fertilizer in thoroughly after it is applied.  Better yet, use a generous amount of compost.
  • Generally, groundcovers should be planted in the spring or early summer to allow them time to become established before winter.


  • ​Be aware of vegetable planting times as well as plant compatibility.
  • It should be safe now to plant vegetables such as beans, peas, potatoes, lettuce, carrots, corn and chard.
  • If the soil temperature is at least 60 degrees F, sow cucumbers, squash, melons, peppers, tomatoes and other annuals.
  • Carrots, tomatoes and lettuce mix well, but not will dill.
  • Newly transplanted vegetable plants should be protected from cutworms with collars.  Cut strips of cardboard two inches wide by eight inches long, staple them into circles and place them around the plants.  Press the collar about one inch into the soil.  These collars will fence out the cutworms and protect the stems of the vegetable plants.
  • Cabbage loopers and imported cabbage worms are green worms.  They leave large holes in the leave of plants in the cabbage family.  For control, caterpillars can be picked off by hand or sprayed with Bt (Bacillus thuringiensis), a natural, non-toxic preparation available by various trade names.
  • Stay out of the garden when the vegetable plant leaves are wet.  Walking through a wet garden spreads disease from one plant to another.


  • Experiments in England suggest that sugar water might be a more effective bait for slugs than beer.  Slugs preferred an agar gel containing 2 to 5 percent sucrose (table sugar).  Artificial sweeteners were ineffective.
  • ​Chitin has been found to reduce nematodes in garden soil. Chitin can be found in seafood meal made from dried pulverized crab and shrimp parts.
  • The efficiency of air conditioner compressors can be increased by up to 10 percent if they are shaded by trees or shrubs.  However, if you have an evaporative cooler, let the sun shine on it.  Evaporative units need the sun to operate efficiently.
  • Toads eat cutworms and other insect pests.  Give them a home in your garden by placing inverted, clay flower pots in shady spots.  Chip out a piece of the pot rim to give the toads an entrance to their home.
  • Where earwigs and sowbugs are a problem try trapping them with rolled up newspapers moistened with water.  The insects will hide in the papers by day.  Gather up the traps and dispose of them frequently.
  • Algae and lichens are primitive plants that grow nearly anywhere there is adequate moisture for them.  Although they are often found growing on tree trunks, algae and lichens generally do not harm trees; often they indicate stressful conditions, such as soil compaction, poor drainage, or insufficient fertilizer.
  • Avoid using peat moss as a mulch.  It tends to form a tight mat, virtually impermeable to light rain once it becomes dry.  It is best mixed in with soil as a conditioner.
  • Of the 39 snakes found in Virginia, 35 are beneficial to the farmer and the gardener.  They eat insects and rodents.  Of particular value is the large, black rat snake which consumes large numbers of mice, rats, other small mammals.
  • If you see ants crawling about on garden plants, look for aphids as well.  Some ant species protect aphids, moving them from plant to plant and even taking them underground into the anthill for overnight safety.  The ants do this to ensure a supply of honeydew, a sugary water substance secreted by aphids, on which ants feed.
  • Insect plant galls may be unsightly, but cause no damage to the plant affected.  They are nothing more than an insect dwelling formed when the insect injects a growth-promoting chemical into the plant.  The plant walls off the insect to prevent damage to other tissue, and the insect is protected by the gall until it emerges as an adult.

© 2020 by COMPEDS. All rights reserved.

  • Facebook