Fall gardening tips

The following piece was written by Master Gardener Khursheed Mama, who has received training through Colorado State University Extension’s Master Gardener program and is a Master Gardener volunteer for Larimer County.

Here are a few suggestions during the fall months for lawns, shrubs, trees, grasses, and more:


The fall months are a great time to get the lawn aerated (especially if this wasn’t done in the spring) and to fertilize while the grass is still green. When aerating, mark sprinkler heads to avoid damage. Sprinkler systems should be blown out to prevent pipe damage resulting from freezing temperatures. This may be preceded or followed by a final mowing for the season keeping with the mowing height of 2.5 to 3 inches—but it’s important to continue to mow if the lawn is growing.

For more information on turf grass and sprinkler system management, visit the Basic Turf Management fact sheet and the Home Sprinkler Systems fact sheet.

Shrubs and Trees

Most shrubs don’t require special care this time of year. Fall blooming shrubs may be pruned in winter during the dormant season. Spring blooming shrubs such as forsythia and lilacs should not be pruned until after spring flowering. Tender shrubs (e.g., roses) should be mulched around their base during the winter. While leaves may be used to help mulch plants such as roses, if leaf spot was noted during the growing season, it is best to remove leaves so as not to spread the fungus that causes this. Roses should be pruned in the spring as the branches just begin to green up, usually in late April. Hips (spent flower blooms) may be left on the plant for winter interest—hips may turn orange with cooler weather.

Fall LeavesBoth as a result of altitude and the angle of the sun during winter months, young trees planted in the last couple of years should be wrapped (using tree wrap available from nurseries) from the base to the first or second branch to help prevent sun scald. Like shrubs, trees may be pruned in the winter months when dormant; pruning should not exceed 20-25 percent of the canopy. Recommendations on “wilt-proofing” evergreens vary. If the plants are in a dry, windy area, newer evergreen plantings might benefit from application, with the recognition that this will likely need to be repeated a couple of times during the winter season. More effective is to wrap shrub and trees with burlap. Winter watering, as suggested below, is likely to have greater benefit.

While automated sprinkler systems should be turned off and blown out for winter, trees and shrubs benefit from winter watering in our dry climate. The general recommendation is to water deeply around the dropline about once a month if there has been limited moisture and ambient temperatures allow.

For more information on recommendations related to trees and shrubs, visit:

Pruning flowering shrubs
Winter watering

Perennials and grasses

fall_gardening_1These represent a diverse range of plants in our Colorado landscapes. For those who enjoy the aesthetic of seed heads in the winter landscape these may be left on the plant. Otherwise, plants may be deadheaded and cut back, but it is best to leave some foliage to protect spring growth. Old foliage may be removed in early spring. Perennial grasses are typically cut back in the spring prior to emergence of new growth.

For more information about choices and care of grasses and perennials in the landscape, visit the Ornamental Grasses fact sheet and the Perennial Gardening fact sheet.

Additional considerations

Water features that aren’t running during winter should be drained or covered. Pumps can be removed and stored appropriately to prevent damage from fluctuating winter temperatures.

Tender plants that you wish to overwinter, like geraniums or herbs, may be placed indoors, in sheltered areas or in the garage and tended to as appropriate (water/sunlight, etc.).

Non-hardy annual bulbs, like dahlias and gladiola, should be dug up and stored in a cool, dark place. Perennial or hardy bulbs may still be planted if the ground is unfrozen and can be dug easily. Many varieties are available from local nurseries and online catalogues.

More information

For more information about CSU Extension, visit www.ext.colostate.edu.

CSU Extension in Larimer County

CSU Extension in Larimer County is a county-based outreach of Colorado State University Extension that provides information you can trust to deal with current issues in agriculture, horticulture, nutrition and food safety, 4-H, small acreage, money management and parenting. For more information about CSU Extension in Larimer County, call (970) 498-6000 or visit www.larimer.org/ext.

CSU Extension Horticulture Agent blog

Looking for additional gardening information? Check out the CSU Extension Horticulture Agent blog at www.csuhort.blogspot.com for timely updates about gardening around the state.

PlantTalk Colorado

Visit PlantTalk Colorado for fast answers to your gardening questions. PlantTalk is a cooperation between Colorado State University Extension, GreenCo and Denver Botanic Gardens.