Year-round gardening: Don't let May overwhelm you

By: Eileen Tully Colorado Master Gardener
May 4, 2013
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May is the be-all and end-all of the gardening year so it's easy to get overwhelmed.

The most important garden tasks for 2013 - a year of wise water use - are listed here.

Early May

Clean and sharpen tools, change lawnmower's oil, sharpen its blade and replace its air filter if needed.

Aerate the lawn with 3-inch plugs while it's moist, and leave them on the lawn. Core aeration helps eliminate thatch and allows oxygen, water and nutrients to flow into the root zone. This is a key step in maintaining a healthy lawn during drought and water restrictions.

Mow to 3 inches and mow often enough that you don't remove more than 1/3 total height.

Begin weed patrol. Controlling weeds before they develop seed heads saves work later.

If you want to shape mugo pines, pinch or cut two-thirds the length of the 'candles ' of new growth. You can use this pinch method with other pines as well.

Plant perennials, bush fruits such as raspberries, potted roses, container grown and balled and burlap trees and landscape shrubs. Look for perennials registered as 'Plant Select. ' These plants are grown for our region and will thrive. Most will be labeled drought tolerant but do remember all new plants require water until they are established.


Thin seedlings of early planted crops such as carrots, lettuce, spinach and beets.

Stake peonies and delphinium.

Continue your weed watch. You can use an organic weed killer of 75 percent vinegar and 25 percent lemon juice on weeds growing in driveways or sidewalks. Don't use this on lawns or in gardens as it will kill flowers and grass.

After early spring bulbs have bloomed, dead-head faded flowers but don't cut the leaves until they have yellowed. Once leaves have died, they easily should pull from the ground. If you plan on moving bulbs in the fall, mark where they are planted with colored golf tees.

Feed roses a balanced rose food every six weeks.

Check containers and prepare for planting. If there was disease in any of them last year, don't reuse last year's soil. Clean those containers with a solution of 1 part bleach to 10 parts water.

Depending on your location, start planting annuals. In many parts of Colorado Springs, it's safe to begin planting tender annuals. Check the weather and your elevation. It's not unusual to have a hard freeze in late May.

Plant summer bulbs that can remain in the ground over winter such as Crocosmia 'Lucifer ' and some varieties of summer Alium.

Begin planting gladiolus every two weeks through June for a continual series of blooms.

If weather remains warm, transfer seedlings outside but harden them off in a sheltered location for a week before planting. Average last frost date is May 10 to May 15.

Late May

For warm season vegetables: make sure the soil is warm. Transplant tomatoes, setting the plants an inch deeper than in the pot.

Plant seeds of corn, bean, pumpkin, squash, cucumber, and early-maturing melon seeds if the soil is warm.

Plant eggplant and pepper bedding plants if the soil has reached at least 50 degrees.

Prune early spring-flowering trees and shrubs such as lilacs and forsythia after flowers fade.

Fertilize lawn (or during the first week in June) using one pound of nitrogen per 1,000 square feet.

Harvest asparagus stalks larger than 3/8 inch until about the end of June. Cut just at soil level.

Plant seeds of flowering annuals outdoors: suggested vines are Hyacinth Bean (Lablab purpureus), Cardinal Flower (Ipomoea quamoclit) and Black-eyed Susan (Thunbergia alata).

Zinnias and Nasturtiums are other annuals that can be planted directly in the soil.


When you have questions, call the Master Gardener Volunteer Help Desk at 520-7684 or email CSUmg2@el Volunteers are available 9 a.m.-noon Monday through Friday.

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