September Gardening Tasks – What To Do In The Northern Rockies

Colorful Autumn Leaves With A Rake
(Image credit: Elenathewise)

The northern Rockies region, aka West North Central, is an area with distinct seasons, including hot summers and cold winters. That means that the in-between seasons of spring and fall are transitioning periods. If you are wondering what to do in the northern Rockies in early fall, the gardening to-do list is long. 

September gardening tasks in this area include completing the summer harvest, transplanting trees and shrubs, and preparing the entire landscape for winter’s worst. Read on for details.

West North Central Gardens

Montana, the Dakotas, Wyoming, and Nebraska comprise the northern Rockies region of the country. Fall weather is brisk and cool, perfect for finishing up the summer harvest and getting the garden ready for winter. 

West North Central gardens are wrapping up in September. The leaves of deciduous trees and shrubs may be starting to turn colors, while vegetable gardens and summer flowers are dying back. 

Completing the harvest is one of the important September gardening tasks in this region. You need to bring tender fruits and vegetables in before the first frost. Pick pears at the hard ripe stage, then let them finish ripening off the tree. 

Gardening To-Do List

Gardeners in the northern Rockies won’t be planning or planting winter gardens. That doesn’t have to mean that all planting is off the table though. In fact, your gardening to-do list for September will include both planting and transplanting.

Let’s talk about planting first. September in the northern Midwest is the time to plant garlic, so get your trowels ready. It’s also an ideal moment to put in bulbs for spring blossoms. Tulips, daffodils, narcissus, allium, and snowdrop need to get into the ground before those frosts. If you have a cold frame, you can install greens like lettuce and spinach.

Thinking of adding trees, shrubs, or a new stretch of lawn? Early autumn is the time to plant new trees and shrubs of any kind. Planted in September, the roots will have sufficient time to establish before new growth begins in spring. If you are starting new lawn grasses from seed, do it now.

Transplanting is not all that different from planting, except that you first have to dig up the rootball before you put it in the ground in a new location. If you decide to change planting sites for trees, shrubs, or perennial flowers, it is one of those September gardening tasks that is best accomplished in fall.

While you are digging up the perennials like peonies, lily-of-the-valley, or phlox, consider whether you need to divide them as well. If so, use a sharp tool and section the roots cleanly. Then install each root section in its own site. 

Other September Gardening Tasks

September is a great time to add compost to the soil to renew the nutrients. Dried leaves can be shredded and worked into the garden beds as well to add organic content. 

Any herbs you want to save still growing in the garden? Be sure to dig them up and pot them so that they can spend the winter inside. Caladiums can’t winter outside either, so dig them up and bring them in to dry and store. If you are the seed-saving type, collect some from your favorite annual flowers and store them for spring in a dry, cool space.

Teo Spengler

Teo Spengler has been gardening for 30 years. She is a docent at the San Francisco Botanical Garden. Her passion is trees, 250 of which she has planted on her land in France.