CO-Horts Blog

Monday, April 30, 2018

Colorful Groundcovers for Mountain Communities

Posted by Mark J. Platten, Teller County Extension Director for Colorado State University

Courtesy of Joy Reis
Ground covers can add interest and texture to your gardens and landscape while helping with ero­sion issues as well.
When choosing a ground cover you should consid­er the length of the growing season, exposure and soil characteristics and cultural needs of the plant. Always amend your soil for better results. Be sure to choose plants that are hardy to USDA zones 2 to 4 for best results. Also consider the size of the area to be covered, steepness of slope and pedestrian traffic volume. Cultural factors to consider are soil texture and organic matter content, moisture and drainage, light exposure and micro-climate for the area in which you wish to plant. 

To cover large areas look for plants that trail, creep, form mats, or spread by runners or rhizomes. Aggressive plants can spread into the landscape. For steep slopes, use species that produce dense, fibrous roots to help prevent soil erosion. Not many ground covers will tolerate repeated foot traffic except for grasses.

Courtesy of Joy Reis
When purchasing your plants, select stock that originates from areas similar to yours since these tend to be hardier. Look for healthy plants that are not root bound or stressed in any way.

The best time to plant in our area is immediately after the last frost, which can be middle to late June in the mountain communities. Before planting, it is a good idea to acclimate your plants by gradually exposing them to longer periods outside over the course of a few days or weeks. This is known as “hardening” off. If the plants are grown outside at local nurseries this will not be necessary.

Our mountain soils generally benefit from amending with organic composts, sphagnum peat moss, composted horse or alpaca manures or a combination of these. Beware that if the horse manure is not properly composted, you may have weed seeds in the amendment. Another option to amending our mountain soils is to create and plant on a berm or raised bed. These options create drainage that is required by many garden plants.

Courtesy of Tami Sluder
Most ground covers will require at least two years to establish. Snow cover acts as an excellent mulch in the winter months. It allows the root growth to occur during some periods of the winter. You can encourage snow to drift over the root zone by placing a snow fence a few feet upwind from the area. 

Some ground covers to consider for mountain regions:
Prickly Thrift Dead Nettle
Wooly Yarrow Penstemon varieties
Bugleweed Creeping Phlox
Lady’s Mantle Soapwort
Courtesy of Joy Reis
Rockcress Stonecrop sedum
Mountain Sandwort Hens and chicks
Sea Thrift Lambs Ear
Basket of Gold Wild Germander
Snow in summer Thyme
Iceplant Speedwell
Pinks Wild Strawberry
Sweet Woodruff Creeping Baby’s Breath

Most of the plants listed are easy to grow. One of my favorites is the Dragon’s Blood Sedum. It spreads very well and has nice color and texture. Some are deer and rabbit resistant. Others are good for borders or to line pathways. Get creative by mixing different textures, colors and bloom times.

Thursday, April 26, 2018

Native plants that serve as “gateway drugs” for the newbie

By Irene Shonle, CSU Extension in Gilpin County

I frequently give talks on native plants to a wide variety of audiences.  Some people eagerly embrace native plants for the habitat they provide, for the reduction in water bills, and for the color and sense of place.  Others are a little more skeptical, worrying either about the rangy appearance of some natives, or wanting them to fit into an already amended and irrigated yard.

So, I have selected some native plants that are of a refined appearance that can be planted even in the strictest of HOAs. You may be so pleased with these gateway natives that you’ll soon be planting more!

Sundrops (Calylophus serrulatus) blooms heavily from late spring to late summer – this is rare for any perennial, much less a native plant.  It has bright yellow, four-petaled flowers that provide as much color as most annuals. It excels in the hotter, drier areas of your yard, where many standard perennials may suffer. While it prefers a lean soil such as dry clay or sand, it will perform well in a light loam if no new amendments are added. It is hardy to zone 5. There is a selection from Plant Select called ‘Prairie lode’ with a more compact growth habit than the straight species.
Calylophus serrulatus 'Prairie lode'  - courtesy Plant Select

Harebells (Campanula rotundifolia) is a plant no garden should be without. It has small beautiful purple bell-shaped flowers on delicate stems that bloom for a long period of time. The color mixes nicely with almost any other color in the garden (except perhaps electric blue).  It would look beautiful with other natives, but also with roses, lilies, and other perennials.  It usually grows between 1 and 2 feet tall, spreads only by seed, and is hardy to zone 2.  It will grow in most soils, and at lower elevations would prefer afternoon shade and regular irrigation.
Campanula rotundifolia - harebells

Bee balm (Monarda fistulosa) is a beautiful mid-summer bloomer with dusky pink flowers. The flowers attract hummingbirds and other pollinators, and the foliage is fragrant (can be used as an oregano substitute) and thus is critter resistant. It grows well in sunny conditions in most soils, including clay, and better yet, it is not as prone to the powdery mildew that afflict many of the more cultivated species.  It gets to be about 2-3 feet tall, and is hardy to zone 4.
Monarda fistulosa, bee balm

Scott’s sugarbowls (Clematis scottii) is a charming plant that would do great at the front of a border or in a rock garden. It has nodding purple flowers and mounding, lacy foliage. Bumblebees love the flowers, and when they crawl inside, their buzz is amplified in a delightful way. They will grow in a wide range of soils, and are drought-tolerant but will not flop if given a little extra water.
Scotts sugarbowls - Clematis scottii courtesy Plant Select

Serviceberry (Amelanchier alnifolia) is a refined native shrub that I am starting to see planted more in public spaces. It has small white flowers in the early season, and blue, edible fruit in the summer.  It is great for attracting birds (which is code for you better net the plants if you want to eat the fruit). The beautiful orange-red of the fall foliage provides another season of interest.  This should be used way more frequently!
Serviceberry - Amelanchier alnifolia

Boulder raspberry (Rubus deliciosus) has gorgeous, large white flowers that look like roses.  This shrub grows happily in shady to sunny conditions at lower elevations (prefers full sun in the high country).  It attracts pollinators in flower and birds in fruit (although the fruit is dry and mealy, and not delicious, in my opinion). In the winter, the bronzy branches with peeling bark provide another season of interest.
Boulder raspberry Rubus deliciosus

Finally, columnar junipers (Juniperus scopulorum cultivars such as ‘Woodward’, ‘Skyrocket’ or ‘Medora’) can provide a little taste of Italy while still providing drought tolerance and winter hardiness.

Monday, April 23, 2018

It's a Weedy Spring

Posted by Mary Small
Colorado Master Gardener State Coordinator
It’s spring and I have weeds. Rather, my landscape does. Both annuals and perennials are making their appearance – but I thought we’d look at a few annuals in this post. Remember that annual plants germinate from seed, grow, flower and go to seed in one years’ time.

Mouseear chickweed
This particular one (Mouseear chickweed – Cerastium vulgatum) is a newer resident on the property and seems to be adapting quite well to this gravel strip between the sidewalk and driveway.
Chickweed is a winter annual, meaning that it germinates in the fall and grows in early spring.  The stems and leaves are sticky from glandular secretions.  In addition, they’re weak and break easily, often leaving part of the plant behind. Meaning rummaging around in the gravel is needed (in this case) to get the whole thing out.

Incidentally, this is a good example of why gravel mulch laid over landscape fabric is not a great idea from a weed management perspective.  Wind blows soil around and eventually  it filters into the gravel on top of the landscape fabric. Wind- blown seed germinates and grows in the soil.  If the roots stay on top of the fabric, plants are usually not too difficult to pull. But if they move into the underlying soil, say through an opening in the fabric, they’re a lot harder and more time consuming to remove.
Prickly lettuce. Note prickles on centermost leaves.
The next weed is prickly lettuce (Lactuca serriola). This is a summer annual – which means it germinates and emerges in the spring or early summer.  It’s easy to pull out when young. The root system is quite small and there’s often a central stem to grab onto. It’s harder to pull when mature, though, and often breaks off at the soil line. Gloves are a necessity at this point, too - it’s not named prickly lettuce for nothing! This weed  grows rapidly in a short period of time. Watch for the ones you missed early hiding in shrubs or perennials throughout the season. Can you find it in the photo of the pansies below?
Prickly lettuce hiding in pansies

Shepherd's purse with tubular seed capsules
Can I just say I really dislike shepherd’s purse (Capsella bursa-pastoris)? That’s because this winter annual is often up and running on the south side of the house before I’m even thinking about weeds. Fortunately, they’re easy to pull due to a shallow root system. Shepherd’s purse has some interesting common names like Mother’s heart and  Witches’ pouches. Those names must be a reference to the interesting- looking, heart-shaped pods some of these plants possess.

Henbit (Lamium amplexicaule) – another winter annual - at least has pretty purple-pink flowers going for it. Henbit is a member of the mint family with square stems. Unlike many other mint family members, though, the root system is mercifully shallow and easy to pull in the spring.