Gardening Tips for May for Woodinville, WA

Northwest Region

  • Fertilize your rhododendrons and azaleas with an acid-based fertilizer if needed.
  • If soil temperature is above 70 degrees, you can now plant eggplants, melons, tomatoes, squash, and peppers.
  • Manage weeds while they are small and still growing.
  • Watch out for pests in the garden. Trap moles and gophers as new mounds appear.
  • Check your plants for any insects, such as aphids, cabbageworms, black beetles, and root maggots and control as needed. (See our Pest pages for advice.)
  • When the soil is warm, apply a layer of mulch around your plants as long as there are no weeds. Mulch discourages weeds and helps to conserve moisture.
  • Continue to mow your lawn regularly. If you use any lawn food, be sure to keep it away from your plants.
  • Lay soaker hoses or drip lines on garden beds to conserve water.
  • Plant bedding flowers in moist soil and remember to keep them well watered.
  • Prune your flower shrubs after they have finished blooming—azaleas, forsythia, lilacs, and rhododendrons. You can also prune evergreens once new growth appears.
  • Fertilize your roses and check for diseases; treat if needed.
  • Cut back spring-blooming perennials to about 3 inches in height after they finish blooming. Sow more perennial seeds and set out new perennial plants.
  • Plant dahlias, gladioli, and tuberous begonias.
  • You can sow hardy annual seeds now, such as calendula, cosmos, and sweet peas.