When summer gives way to fall and the aspens start thinking about a wardrobe change, Colorado gardeners are nowhere near ready to hang up their tools. Sure, there are plenty of end-of-season chores to keep us busy, but it’s also a good time to get many ornamental and edible varieties in the ground and from a local Denver nursery. So what can you plant in the fall in the Denver metropolitan area? Let’s take a look:
Spring-flowering bulbs
Some of the earliest flowers to bloom in spring are bulb plants, and here in the Denver area, early September to mid-October is bulb-planting time. That’s because everything they need to get a head start, they stored up in a tidy little package during the previous growing season. Bulbs are the plant’s equivalent of dehydrated backpacking dinners: Just add a little heat and water, in the spring and they’re good to go.
This is a bonus for new gardeners or those who haven’t had the time to perfect their bedding soil. As long as bulb beds drain reasonably well and are situated where they get full sun, these plants are foolproof and perfect for the novice.
“Be sure to choose fresh, firm, plump bulbs!” says Bethany, an avid Arvada gardener. “You never know how long big-box stores or online retailers have kept theirs in a warehouse.”
Bulb plants come in all shapes, sizes, colors, and bloom rates. You can go for a riot of colors using Dutch hybrid varieties, or a more understated (but no less spectacular) native Colorado theme with snowdrops, daffodils, crocus, and iris.
Deciduous trees and shrubs
While evergreens prefer to put down their roots in spring, September and early October are ideal for planting dormant deciduous trees—and you’ve got plenty of options suitable for our Rocky Mountain Front climate. In fact, several years ago the region’s top horticulturists, landscapers, nurseries, and urban foresters got together to brainstorm the best candidates for Colorado’s soil and climate and created the Front Range Tree Recommendation List.
But even that can be a bit overwhelming, which is why we encourage homeowners to consult with our gardening pros at a local Denver nursery. We can help you fine-tune your selections according to your location, personal aesthetic, and property layout. Other things you might consider:
- Tree size: Choose trees that won’t interfere with overhead or underground utilities, block too much sunlight, or encroach upon your neighbors’ or public space.
- Aesthetics: Trees and shrubs anchor your landscaping. Bark colors and textures, canopy shape, and shade density influence the annuals and perennials you’ll select to complete your design.
- Growth rate: If you’re looking for a natural privacy fence, choose shrubs and trees that rapidly grow and close the gaps between specimens. Some trees that grow quickly may not be as resilient in windstorms.
- Water consumption: All young trees require frequent watering to get established, but as they mature, your landscape irrigation scheme, designed to maintain lawns and lush annual beds might “overdose” them with moisture.
- Maintenance (and messiness): How difficult are leaves, seedpods, and fruits to clean up? How often does the specimen require pruning?
- Habitat value: Some trees and shrubs provide food and cover for birds, deer, pollinators, and small mammals. For some Denver homeowners, these are positives; for others, well, see above.
One thing most young deciduous trees and shrubs have in common: They’re surprisingly easy to transplant and establish, even for beginners. And the right landscaping trees and shrubs increase property values, decrease energy costs, and create soft, pleasing spaces out of otherwise angular lots.
Cool-season vegetables in cold frames
The best time to plant cool-season vegetables outdoors for fall in Colorado is late July through early August, but if you missed your window… well, build a new one!
Set up a cold frame in a south-facing section of your garden—particularly one that’s protected on its north side by a structure or wall— and grow low-profile, cold-hardy produce such as lettuce, bok choy, kale, spinach, and cauliflower—just for starters. You’ll have fresh veggies throughout winter, and the perfect place to give spring seedlings a head start!
“DIY plans are easy to find,” said Rob, who maximizes his Wheat Ridge duplex growing space with cold frames, raised beds, and patio containers. “Look for old windows on Craigslist, but avoid glass if you have rowdy kids or pets. Corrugated plastic works great.”
Microgreens
If you don’t have a cold frame, you can still grow crunchy, flavorful, nutritious “baby” greens outside up to two weeks before our first fall frost. You can even grow them indoors year-round with little hassle.
Microgreens is a broad term applied to vegetables sprouted in fine soil for the purpose of harvesting before maturity. Any type of flat, draining container, filled two inches deep with sterile seedling mix works great for indoor microgreens, or you can plant them in newly-harvested raised beds.
Here are just a few favorites:
- Mustard
- Cress
- Radish
- Turnip
- Mizuma
Keep an eye out for microgreen mixes, and experiment to find your ideal balance of sweet and spicy!
Windowsill herb garden
If you’ve got a sunny window, create an indoor kitchen herb garden. Tender herbs are the most beginner-friendly, but they’re also the most popular culinary seasonings. These herbs are easy to grow indoors and will inspire you to create more flavorful meals at home.
- Chives
- Basil
- Parsley
- Cilantro
- Oregano
- Mint
- Catnip
If you need a little extra light or you don’t want to clutter up your kitchen window view, you’ve got affordable and space-saving options, thanks to LED technology.
Grasses
Do you need to re-seed a tired lawn, or start a new one? Grasses establish roots within a couple of weeks, and fall’s a good time to get them going: Cooler temperatures and more frequent rainfall is exactly what they need to get established. Choose cool-season grasses for fall-seeded lawns; we recommend Kentucky Bluegrass or a fescue/Bluegrass mix.
Golden gardener and dog lover Amy has good advice for preparing pet-damaged lawns: “Dog urine is alkaline. Thoroughly water the patches and surrounding area, do a home pH test, cultivate the soil with an acidifying amendment, and plant fresh lawn seed. And train your pet to use an out-of-the-way corner of your garden.”
Clumping ornamental grasses are best established in spring, but you can transplant nursery starts in September, so they get a chance to dig in their roots by our October 15 frost date. Give them extra protection with mulch.
We’re your year-round gardening mentors
Whether you’re transplanting perennials, trees, shrubs, or bulbs in the fall, be sure they’re healthy and undamaged from shipping. Your best bet is purchasing starts and saplings raised in your own climate. Country Fair Garden Center sources its stock from a local Denver nursery, ensuring you’ll have the best chance at success. Need a little coaching? Our gardening pros are happy to answer your questions and offer advice whenever you need it!