May Garden Tips


Garlic mustard.  This highly invasive plant has arrived and is threatening our forests.  In some areas it has all but eliminated the native forest floor plants, and even has the ability to stop the germination of some tree seeds.  You are most likely to find it around the edges of your lawns and gardens, in disturbed areas, under shrubs and so forth.  Pulling it whenever you see it is the first line of defense.

Gypsy moth and winter moth caterpillar check.  The Massachusetts Department of Agriculture reports that gypsy moth caterpillars are emerging from the egg masses laid in trees last fall.  Check trees on your property daily for signs of them.  If you see tiny caterpillars, it’s time to act.  BT-K (Bacillus thuringiensis K) is an environmentally friendly spray available at local nurseries.  When the caterpillars ingest the BT-K, it will kill them.  But even with this, please use it carefully and read the application information.  Our thus-far wet spring offers hope that, in future years, a naturally-occurring fungus will keep the population of gypsy moths in check.

Feed your bulbs now — before, during, or after they have bloomed.  This helps the foliage to send food to the bulb which it will use to grow next spring’s flowers.  Do NOT cut off foliage, or braid it until it has turned yellow, or you will not have blooms in 2018.  Hate the look of yellowing foliage?  Plant annual among them to hide it.  As the flowers on your spring bulbs wilt, do them a favor and pop off their heads.  You want your bulb to put its energy into producing more bulbs, not producing a hybrid seed from whatever pollen it received. 

Don’t let weeds get a start in your garden!  Weeds in flower beds are usually easy to spot and so are pulled early.  Do the same in your vegetable garden.  Weeds are thieves of water, light, nutrients and the precious room to grow.  Weeding early means they don’t get to set seeds and make more weeds.

Plant a pollinator garden.  Want to do a good deed for the bees and butterflies in your neighborhood?  Plant a small pollinator garden.  Find a sunny spot anywhere on your property and clear a space.  Plant seeds at the depth specified on the package.  Here’s a quick list of flowers that grow easily from seed and benefit the environment: bachelor buttons, cosmos, nasturtium, poppies, and zinnias.  Keep the area you planted watered until the new plants have grown.  Seeds that dry out won’t sprout. 

Steer clear of neonics.  As you visit garden centers looking for annuals and perennials for your garden, you may well encounter plants with tags like the one pictured (some are prominent, others are buried).  They say the seeds that grew the plant were treated with neonicotinoids, a neuro-toxic pesticide.  When seeds are coated with this pesticide, the pesticide will appear in every part of the plant-leaves, flowers pollen-making the plant deadly to insects that come to pollinate it.  These tags have even been found on milkweed (grown to feed butterflies) for sale in the South at Home Depots.

Want shorter, stronger flowers?  Pinch back chrysanthemums at the end of May.  The same treatment works well with any perennial that is growing now but won’t bloom until fall.

  • Divide summer- and fall-flowering perennials before plants exceed 6 inches tall. If spring rains are scarce, don’t forget to water newly transplanted divisions.(Extras go to our Plant Sale!)
  • Tackle weeding while invaders are small. Hand-dig offenders with an Asian hoe, putty knife, or other favorite tool. Weeds pull easiest when soil is wet.
  • Wait to prune spring-flowering shrubs (such as lilacs, mock oranges, weigelas, many types of viburnum, etc.) until after blooms fade. Prune immediately after flowering to avoid hindering next year’s show.
  •  Give the compost pile a turn or two after spring rains start. Turning the pile even a little helps work moisture throughout, which jump-starts spring decomposition.
  • Wait to mulch planting beds and vegetable gardens until later this month — when soil has warmed. Don’t cover soil until after self-sowers have sprouted and there’s a need for mulch to retain soil moisture and shade weeds.
  • Add a shovelful (or two) of compost to roses, clematis, butterfly bush, and delphinium. You’ll be rewarded with more blooms and bigger plants.
  • Start pinching garden mums as soon as shoots are 4 to 6 inches long. Remove the last inch of growth until early July and you’ll enjoy bushy plants loaded with flowers in fall.
  • You can also pinch back other late-blooming perennials such as sedum to keep them more compact in autumn.
  • Insert stakes now to prevent flopping later with plants like peony, aster, or false sunflower. To avoid accidentally spearing dahlia tubers, add stakes at planting time when you still tell where the tubers are.
  • To keep the soil from seeping from a container’s drainage holes and creating a mess, place a fine screen or coffee filter over the hole before filling with soil.