Does Fall Planting Work in Colorado?

Most Coloradoans plant in spring. But fall can be a great time to tuck a few extra plants in your landscape.

Here are a few reasons why. First, you can see bare spots in your yard easily since most plants have reached their full size for the year. Second, the soil is warm, which encourages new roots to grow. Third, many plant nurseries mark down their stock so they don’t have to overwinter plants.

Goldsturm black eyed Susan is a beautiful late summer perennial flower for Colorado landscapes.

So, is fall planting worth the investment?

Yes, but only if you’re very dedicated to winter watering.

Over the 20 years I’ve worked in landscaping, I’ve tried planting in all seasons. I’ve even planted right before Thanksgiving when most landscapers are on vacation in Mexico. I’ve had great successes and dismal failures.

Here’s what I’ve learned are the keys to successful fall planting:

Choose small, stocky plants with few flowers.

The plants you install in fall are going to go dormant very soon after planting. Don’t choose the huge, floppy, tired plant that’s been growing in a pot all summer at the garden center. Instead, choose small plants preferably without flowers.

Plants without flowers will have an easier time transplanting and making it through winter dormancy. They are still in the vegetative stage of growth, meaning that they’re focused on growing, not flowering. Because of this, they can easily invest resources in root growth. Flowering plants are focused on, well… flowering.

You can plant until the soil freezes, but it’s better to plant before October 1^st.

Most of Colorado’s Front Range will get a hard frost around October 15^th. If you plant before October 1, that gives the new plants 2 to 6 weeks of ideal growing conditions before they lose their leaves. For perennial flowers and ornamental grasses, this can be enough time to grow roots into the surrounding soil.

If you plant after October 1, there’s a good chance the plants will not grow many roots until the following spring. They frost will kill their leaves, causing growth to slow down dramatically.

It is critical to water fall-planted plants.

If you talk to long-term Colorado gardeners, you’ll find they are black or white on the fall planting issue. After studying this dichotomy for many years, I’ve concluded that the people that are successful at fall planting are diligent at winter watering.

If you decide to plant in fall, make sure you water once or twice per month, every month until you turn your sprinkler system on next spring. This prevents the plants with tiny root systems from dehydrating and dying. I winter water native landscape plants for two winters, and most introduced landscape plants for three or more winters.

If you will be busy in the winter or don’t want to stand outside with a hose in the cold, save yourself and wait until spring to plant.

Perennial flowers, groundcovers and ornamental grasses are easy to fall plant. Shrubs and trees are trickier.

Small, herbaceous plants grow new roots quickly. Larger, woody plants take longer.

If you’re thinking about fall planting trees or shrubs, make sure you follow these guidelines.

• After you plant, make sure you mulch the edges of the root ball well, but keep the mulch away from the trunk to prevent bark rot.
• Monitor the moisture carefully in the root ball and surrounding soil. It should be moist but not soggy.
• Keep in mind that evergreens will continue to use water over the winter, so they’ll need slightly more water than a deciduous tree or shrub.

Visit this link to read my article on nine steps for successful planting.

In conclusion, if you’re still enthusiastic about enhancing your yard, fall can be a great time to plant in Colorado. Just make sure you plant stocky plants before October 1 and winter water them regularly. By next summer, they’ll no longer look like the new kids on the block. They’ll be beautiful additions to your landscape.