“Is it too late to start a garden here in the Denver area?” Once July rolls around, our staff hears this question every day, without fail. Our answer? Absolutely not! That’s good news for locals who’ve spent their summers preparing their yards for new landscaping features, or those who’ve put off yard work in favor of enjoying the beauty of Rocky Mountain backcountry.
You’ve got plenty of time to bring a little Colorado wilderness home with stunning native plant species, and there are plenty of classics popular in gardens around the world. This is the time to establish perennial plants and shrubs for years of enjoyment.
Perennials Vs Annuals… What’s The Difference?
If you’re new to gardening, you’re not alone in wondering what these terms mean. Perennial and annual refer to a plant species’ lifecycle and maturity rate, indicating when you can expect blooms and—for edible plants—fruits and vegetables.
Annuals Complete Their Entire Life Cycle In A Single Season
Annual plants grow anew from seed each year. They’re usually quick to mature, and they completely die back at the end of the growing season. These plants tend to produce spectacular flowers since they have to drop enough seeds to support future generations. Most garden veggies are annuals.
Perennials Regrow Each Year From The Same Root System
Perennials often last years, and they’re generally hardier than biennial and annuals. Their foliage usually drops or dies back each fall here in Colorado, but their roots remain dormant through winter. In early spring, established perennials are often the first to green up the garden and add colorful blooms to your landscape.
When Is A Perennial Not A Perennial?
Some plant species are technically classified as perennials, but only grow year-around in warmer climates. Here in Colorado, they’re grown as annuals and replaced each spring, since their roots can’t survive our cold winters. There are workarounds, though! Some spectacular varieties are suitable for container growing, and you can bring them indoors before the first hard frost. You can dig up and store bulbs and tubers for spring replanting, or try your luck covering your garden beds with a thick, insulating layer of mulch.
Which Perennials Are Easy To Grow Here In The Denver Area?
Not all perennials do well in our region, but the Denver metropolitan area has a surprisingly agreeable climate. According to the revised USDA Plant Hardiness Zone Map, local gardeners can expect success with perennial species suited for zones 6a and 5b. If you’re unsure, our knowledgeable staff can give you specific recommendations for your particular area, whether you’re in Arvada, Golden, Parker, Wheatridge, Centennial, Lowry, or somewhere in between. If you’re on the adventurous side, ask us how to make your garden more hospitable for more finicky warmer climate varieties!
Want a low-water, low-maintenance garden? Some of your best options are perennials native to the Colorado Rockies, especially suited to our local soils and weather.
We offer a wide selection of nursery starts, but many of our customers enjoy starting their perennials from seed. Either way, you’ll transplant your young plants into large containers or prepared beds.
Get A Head Start With Young Nursery-grown Perennials
Most perennial plant species are tricky to grow from seed, so we recommend novice gardeners purchase healthy nursery starts for the best chance at success. Here in Colorado, early spring or late summer are ideal seasons for transplanting perennial “starts”. The plants are channeling their energy into growth, rather than flower production, and they’re less likely to experience heat stress—a problem for plants that haven’t established strong root systems.
Most Perennials Are Low-maintenance Plants
Once established, perennials suited for the Denver area require little to no coddling, and they’re forgiving of rookie mistakes and a bit of neglect. Woodier perennials such as lavender and rosemary need pruning after their first year, and most species require dividing after three or four growing seasons. Neither task takes much time, and in the case of the latter, you get new plants with which to expand your garden!
Perennials do enjoy a balanced fertilizer once or twice a year, and as with most plants, they appreciate a layer of mulch to keep weeds at bay and to stabilize soil temperature and moisture.
We strongly recommend hand-watering newly-planted perennials each morning for a month to six weeks to get them established. Once they’re on their way, you might consider installing micro (or “drip”) irrigation. Just be sure to select emitters according to soil type and species to make sure the water seeps deeply enough to encourage healthy root growth.
What Are The Best Perennials For The Denver Area?
Honestly? There are too many perennials compatible with our climate to list here, ranging from low-growing ground covers to flowering shrubs. We’re fortunate that plants native to the Rockies are among the most spectacular species grown in North America, and that our local climate is hospitable to a wider selection than are most mountain regions.
Here are just a few of our favorite picks:
- Columbines: An exotic-looking native perennial that’s tougher than it looks.
- Penstemon: This large, bushy North American native bears colorful flowers on tall spikes. There are many varieties compatible with the Denver area, and they’re popular with pollinators.
- Russian sage: More delicate-looking than traditional sage, this species is tougher than it looks.
- Sedum (stonecrop): These succulent flowering ground covers need little water, and look fantastic in rock gardens or between pavers. There are a seemingly endless number of species that do well here in Colorado.
- Echinacea: Also known as coneflowers, echinacea grow quickly to serve as colorful background plants. You’ll recognize their dome-shaped centers and drooping purple or magenta petals.
- Coral bells: Dainty pink blooms on tall spikes brighten shady areas under trees or along north-facing walls
Did we say “just a few”? Don’t let anybody tell you your options are limited if you want to garden in (or near) the Mile High city.
Gardening Is A Year-around Hobby, Even In Colorado!
Perennials aren’t your only late-season gardening options! Come into our store, call or send us an e-mail and we can help you select cool-season vegetable varieties and ornamental annuals from our nursery. At the very least, we can help you get ready for next Spring’s growing season with tips on soil amendments, garden tools, and accessories, and landscaping ideas using plants ideal for the Denver metropolitan area!