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Happy Mother’s Day

COVID-19 Response: New Castle Gardens is open Mon-Sat 9-5 and Sun 9-3. We are doing zero contact sales. Masks are required. 6-10 foot social distancing. 2 people in the store/greenhouse at a time.

May Garden Calendar


  • Seed or sod new buffalo grass or blue grama lawns.
  • Fertilize cool-season grasses in mid-May.
  • Water established bluegrass lawns deeply and only when needed. Use a trowel and dig down 3 inches to check for soil moisture. If it’s moist at that level, there’s no need to water.
  • Stay on top of weed removal to prevent weed seeds from spreading to your lawn and your neighbor’s.
  • Prune overgrown spring-flowering shrubs such as lilac right after they have finished flowering. Pruning shrubs requires some know-how for healthy growth and future bloom. Hire a professional if needed.

Vegetables and Herbs

  • Prepare the soil before planting out transplants: Remove weeds and large rocks. Work up the soil until it is loose so air and water can reach the roots. Add homemade or store- bought compost if you didn’t do so in fall. Then mix in a slow-release fertilizer based on the size of your planting area.
  • Harvest rhubarb stalks larger than ½ inch in diameter by gently twisting and pulling at the base of the stalk.
  • Harvest asparagus stalks larger than 3/8 inch in diameter until about the end of June. Cut them just at soil level.
  • Enjoy freshly harvested lettuce, spinach, radishes and green onions.

Annuals and Perennials

  • Cut spent flowers from spring-blooming bulbs. Keep the leaves on to provide food for next year’s bulbs. Pull only after they yellow and come out easily.
  • Mark the location where bulbs are growing if you want to move them in the fall.
  • Finish cleaning up roses, pruning dead, weak or old stems to shape the rose. Apply the first fertilizer of the season.
  • Do any necessary “shovel pruning”: Dig out and remove perennials that aren’t working, are underperforming or have died of old age.


  • When using containers for vegetables or blooming annuals, go for a foot wide or larger (especially for vegetables). Small containers dry out too quickly. Drill or poke holes in the bottom for drainage. Cover the holes with a coffee filter and fill with quality potting soil. Fertilize when planting and then on a weekly basis.
  • Group plants according to watering needs and use different leaf and flower shapes to mix it up and make it fun. Plant closely for immediate impact; your plants will do well in a small, cramped space as long as there are drainage holes in the container and you water and fertilize regularly.


  • Look for signs of oystershell scale on lilacs, dogwood, or other woody plants. Scale insects hatch in late May and the “crawler” period is the best time to control them. Neem oil is an effective and natural control.
  • Aphids may curl the new growth of many plants; use a strong spray of water to dislodge them. Then follow up with an organic insecticidal soap.

Adapted from: https://extras.denverpost.com/graphicsdept/gardencolorado/calendar/gardencoloradocalendar.html

Flower & Strawberry Baskets

Fantastic Mother’s Day Gift

Fully Stocked

May Sale

10% Off Horticultural Vinegar

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