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May Garden Calendar – NC Mountains

May Garden Calendar

Plants in Flower

  • Southern Magnolia, Golden Chain Tree, Kousa Dogwood, Hybrid Rhododendron, Mountain Laurel, Satsuki Azalea, Scotch Broom, Deutzia, Beauty Bush, Weigela,  Roses, Clematis, Honeysuckle, Dianthus, Sweet William, Candytuft, Beadered Iris, Peony, Coreopsis, Poppy, and Summer Annuals

What to Fertilize

  • Fertilize summer flowering plants like crape myrtle and rose-of-sharon this month.
  • Do not forget to sidedress or fertilize your vegetable six to eight weeks after germination.

What to Plant

  • Plant gladioli bulbs (corms) this month.
  • Plant summer annuals like begonia, geranium, marigold, petunia and zinnia this month.
  • The following vegetable plants can be set out this month: eggplant, pepper, tomato and sweet potato.
  • The following vegetables can be planted this month: beans, lima beans, cantaloupe, corn, cucumbers, okra, southern peas, pumpkin, squash and watermelon.

What to Prune

  • Prune your hybrid rhododendron after they finish flowering.
  • Prune any hedges that have outgrown their desired shape.
  • Pick off azalea leaf galls if they form.
  • Do NOT cut back spring bulb foliage until it turns yellow and brown.

Pest Outlook

  • Spray the following landscape shrubs for the following insect pests: arborvitae-bag worm, azalea-lace bug, boxwood-leaf miner, euonymus-scale, hemlock and juniper-spruce mites, pyracantha-lace bug and hybrid rhododendron borer.
  • Spray iris beds for iris borers.
  • Spray the following vegetables if insects are observed: cucumber (cucumber beetle), squash (squash borer and aphids, tomato and eggplant (flea beetle), broccoli, cabbage and cauliflower (worms).
  • Continue with rose spray program.
  • Keep spraying your tree fruits such as peaches and bunch grapes with a fungicide program.
  • Use pesticides sparingly. Spray only when needed.

Lawn Care

  • Fertilize zoysia this month after it has greened up. Do NOT fertilize tall fescue now.
  • Start warm season lawns like zoysia in May.
  • Mowing heights for your lawn are important. Cut tall fescue and bluegrass at three inches, zoysia at one inch.


  • Take softwood cuttings of plants like azalea, rhododendron, forsythia, clematis, chrysanthemum and geranium in late May if you have a misting system.

Specific Chores

  • Purchase locally grown strawberries.
  • Move houseplants outside if desired.
  • If weather has been dry, give favorite plants a good soaking once a week.

All Year’s Garden Calendar