Groundcovers

by Ann McKean

The most prevalent groundcover most of us have in our yards is turf grass. Turf is great if you need a groundcover that can take high foot traffic, but many of us only walk on our lawns to push the lawnmower. Turf is the most labor-intensive and resource-greedy groundcover, requiring frequent mowing, faithful irrigation and fertilizer. Many homeowners want their lawn to be ‘perfect’ and apply toxic weedkillers as well. So instead of turf, let’s consider some beautiful low maintenance alternatives.

Many alternative groundcovers can tolerate foot traffic, including creeping thyme, veronica, clover, and ajuga, and some will grow where traditional turf will not, for example, creeping jenny in dry shade under a tree. Some others that thrive in shade are lamium, vinca, heuchera, galium, lysimachia, and geranium. Many are extremely drought tolerant, such as hymenoxys, antennaria, sedum and artemisia. Many non-turf groundcovers bloom throughout the growing season with beautiful and often fragrant flowers, including anemone, phlox, veronica, thyme and convallaria.

Groundcover plants can also serve to add contrast in color, height and texture within a perennial bed. Clumping grasses can be planted in groups as non-traffic groundcover to beautiful effect. Low-growing shrubs can serve as groundcovers too.

Not all groundcovers are evergreen and many do not tolerate wet feet. These respond very well to a mulch of pea gravel instead of wood chips and thus remain functional and attractive even in winter. Others can tolerate more moisture, including the Carex family of sedges.

Blue Fescue makes a beautiful contrast with its soft texture and blue color.

Here is a list of some of the plants that can serve as groundcovers in our climate. Thymus praecox (creeping thyme), Phlox subulata (creeping phlox), Armeria (thrift), Antennaria dioica (pussytoes), Hymenoxys (perky sue), Artemisia Silver Brocade, sedum, Veronica ‘Waterperry Blue’ (speedwell), Veronica Tidal Pool, Trifolium (clover), Cerastium (snowin-summer), Aurinia saxatilis (basket of gold), Oenothera (evening primrose), Callirhoe (wine cup), Iberis (candytuft), Stachys byzantia (lamb’s ears), Stachys officinalis (betony), Nepeta ‘Kitten Around’ (catmint), Potentilla neumanniana (alpine cinquefoil), Fragaria (strawberry – you only mow it once a year), Ajuga reptans (bugleweed), Lamium maculatum (deadnettle), Vinca minor, Galium odoratum (sweet woodruff), Viola odorata, Viola labradorica, Anemone sylvestris, Geranium ‘Karmina’ (beautiful fall color), Geranium ‘Biokovo’, Convallaria majalis (lily of the valley), Heuchera, Lysimachia (creeping jenny – be careful what you wish for), Agrepodium (snow on the mountain – be really careful what you wish for), Mentha spicata (spearmint – it’s awesome, but you’ll never get rid of it), Festuca (blue fescue), Carex glauca (blue sedge), Sporobolus heterolepis (prairie dropseed). Some groundcover shrubs include Microbiotta decussata (russian cypress), Juniperus horizontalis, Prunus besseyi ‘Pawnee Buttes’ (sandcherry), Aronia melanocarpa ‘Ground Hug’, Potentilla tridentata ‘Nuuk’, Salix nakamurana (creeping alpine willow).

Veronica ‘Waterperry Blue’

Finally, if you must have turf grass, consider the native buffalo grass. While still requiring some irrigation, mowing and fertilizer to look its best, the newest cultivars of buffalo grass are even more drought tolerant and weed resistant, and require much less input than traditional sod.

Fall Pruning

by Elizabeth Waddington

Most pruning is done in early spring in that period between dormancy (aka “too stinking cold to be outside for long”) and “oops now it really is spring, and the trees and bushes are leafing out”. However, some pruning can be done in the fall while you still have leaves on the branches and can see where problems have occurred during the current growing season.

Remember to wipe your pruners with rubbing alcohol between cuts (or spray with disinfectant) to avoid contamination to the next cut. Always clean and wipe down your tools before stowing away.

What To Prune

Dead limbs on trees: This is especially important in areas prone to heavy snow or ice. If you know it’s dead, cut it down before bad weather arrives.

Shrub roses: It’s best to tackle rose pruning in winter or early spring when plants are dormant. If you have large or overgrown shrub rose bushes and you’re in an area prone to heavy snows that could break canes, pruning to remove 2 to 4 inches of canes can help protect the plant. If shrub roses have overtaken walkways, remove the problem canes. Wait to prune until after several hard freezes, or you risk triggering new growth.

Perennials with disease issues: This list includes bearded iris, hollyhocks and any plants with a powdery mildew problem, like peony, bee balm and garden phlox. Cut stems back to 2 to 4 inches and destroy (don’t compost) the pruned material.

Suckers: Some plants send up shoots at and/or around the base of the original plant. Cut them as close to the base as possible. Examples include sumac, kerria, saucer magnolia, witch hazel and the colored twig dogwoods.

Natural holiday décor: Feel free to prune a few branches from evergreens, berried twigs and even rose stems with hips to use as outdoor holiday decorations. Plan your pruning cuts carefully, remembering that you’re influencing future growth.

What Not To Prune

• Spring flowering shrubs and trees (azalea, lilac, dogwood, viburnum, oakleaf hydrangea)
• Ornamental grasses
• Marginally hardy perennials (plants you’re not quite sure are coming back until you see new growth in spring)
• Climbing roses
• Perennials that provide winter interest (tall sedum, baptisia, Siberian iris)
• Perennials with seed heads that feed birds (coneflower, black-eyed Susan, anise hyssop, tall liatris)

Breaking The Rules

You can always break the pruning rules if you don’t mind the consequences, such as not having flowers for one year or risking more severe winter kill on stems. A spreading shrub-like forsythia that’s overreaching its space is a good target for pruning whenever you find the time. You can take down a summer bloomer like butterfly bush (buddleia) in early winter, but you might risk losing the plant entirely to winterkill if winter is exceptionally hard. Better to prune stems back to 24 inches, and shorten further in spring once new growth appears.

Not confident with your pruning skills? Check with our County Extension Agent, Amy Grandpre at 406.256.2821 • Email: agrandpre@ co.yellowstone.mt.gov

Planting Trees in Billings’ Boulevards

by Elizabeth Waddington

Those stately trees around town that give our city a “Tree City U.S.A.” designation by the Arbor Day Foundation are not there by accident. Our city employs an arborist and has a process for planting trees in the boulevards (or parking strips, depending on where you previously lived).

You need a permit to plant in that 5 or 7-1/2 foot strip between the sidewalk and street! Contact the city for an application to plant a boulevard tree (Engineering, 2224 Montana Avenue, Billings, MT 59101; phone 406.657.8231). This also applies to pruning or removing a tree on that land.

There is a list of “Recommended boulevard trees for City of Billings”. The list is divided into sections for large, medium and small trees, and provides the common name, the Latin name and cultivar if pertinent. Most trees on the list have some notes about disease susceptibility, special considerations, or suitability to the Billings area. Look over the list of suggested trees and start calling local nurseries (rather than depend on shipped from out-of-state box store stock) to see what they have in stock or can get. Select trees that you are willing to care for (prune, pick up fruit and leaves, etc.) and will not obstruct pedestrians or vehicles on the street. Make sure the watering needs of your tree will easily be met.

Because your application includes a map indicating where you will plant your tree(s), call an underground utilities locator service to determine if you have underground pipes or wires to consider. A comprehensive list will include public and private entities such as water, sewer, cable tv (multiple), gas, etc.

Send in your application and wait for approval in three days to three weeks. When your approval is granted, grab that tree and get it in the ground following the advice of the folks at the nursery and your best practices guidance from the Master Gardeners’ program.

Dr. Bob’s Wisdom

~ Submitted by Corry Mordeaux

Question to Dr. Bob: How should I prune my lilacs?

Lilac is probably the most common flowering shrub in our region. Those fragrant purple or white flowers reinforce just how wonderful spring is. The colorful magenta, red and pink flowers of the hybrid lilacs suggest that the beauty of this plant is boundless. But if not cared for, lilacs soon produce more unproductive wood than flowers.

Prune lilacs for the first time when they are head high. Deadheading (removing dead flower heads) is useful on young plants but is seldom worth the time and effort on mature bushes. The best time of year to prune lilacs is right after they flower. Remove all dead and diseased wood, broken branches, and pest infested canes. Maintain about 12 healthy canes per bush. These should be of different ages up to about eight years old. Older wood is relatively unproductive and may flower only at the top of the plant.

Once the bush is established, remove the oldest one-forth to one-third of the canes each year and select the same number of suckers to replace them. Remove all other suckers or the plant will become choked and overgrown. If you prefer to maintain your bush as a screen rather than for best flowering, let the canes reach the appropriate height and the bush will fill in. It will make a fine screen but won’t produce much in the way of flowers.

If you want to rejuvenate an overgrown bush, remove the oldest canes over a three to four year period and cut back the replacement canes to the appropriate height. Cutting the plants to the ground is a fast way to rejuvenate but causes much shock to the plant.

Dr. Bob’s wisdom lives on.

Book Review

Grow Your Soil! By Diane Miessler

Book Review by Ann Guthals

After the end of World War II, the leftover chemicals like nerve gas were converted to agricultural use as pesticides and synthetic fertilizers were developed. The message became “better living through chemistry,” including for growing our food. Small farms grew to large monoculture operations, we waged a war on weeds with herbicides, and we fed our gardens and farms with synthetic fertilizers.

But look at a place of undisturbed land—a forest, a meadow, a grassland. Who waters it, plants it, feeds it? Yet it thrives. And look at the downside of chemical farming—poisons in the water, soil, and air; loss of diversity in our crops; dirt not living soil.

Many are learning about what goes on in healthy living soil with an intact soil food web and how we can encourage our soil to be healthy without synthetic chemicals. It takes effort to get our heads around what goes on there because except for animals like earthworms we really can’t see what is happening.

This book is about the wonder of the soil food web and how to support and develop it in your garden.

The keys are 1. Not tilling and 2. Encouraging the web with compost, mulch, cover crops, growing plants and no synthetic chemicals.

While there is a plan for starting a new garden plot, this is a book about supporting the soil food web not a book on general gardening advice. If you’ve been learning about this topic, you probably have theoretical and practical questions. My main one currently was: if I don’t till, what do I do with green manure in the spring?

I found my answer here—pull it up, lay it down, cover it with brown. Pulling up the green manure plants doesn’t disturb the soil as much as tilling and leaves root matter behind in the soil. Laying it down and covering it with brown composting matter like straw or wood chips allows the green matter to decompose. When you are ready to plant, you push these layers aside but you keep it several inches away from the planting area as the decomposition utilizes nitrogen. I have also learned to lay my pulled weeds down to add to the layers (though I do discard bindweed and grass with roots attached).

There are also particularly good sections on how to compost and what is mulch, including cover crops.

Worth reading? Yes! You will probably find answers to your feeding-the-soil questions here. The book is concise, packs in a lot of information in a fairly short book, and, if you remember it is not a general gardening book, you will gain a lot of useful information if your questions are about how to support the soil food web.

Movie Review

“Intelligent Trees”

Reviewed by Ann Guthals

This movie features the work and thoughts of Peter Wohlleben (German forester and author of The Hidden Life of Trees) and Suzanne Simard, professor in the Department of Forest and Conservation Sciences at the University of British Columbia. Their dialog and illustrations explain how what’s going on underground in the roots and soil web is as important for a tree as what’s going on in the trunk and leaves.

Why would gardeners benefit from watching this film? We are learning more and more about the importance of the soil food web—seeing it clearly explained for forest soil and trees and seeing the science supporting the ideas helps us under-stand the soil web better as well as communication among trees, so we may transfer and use this knowledge to improve our garden soil and understand our plants.

Peter Wohlleben is fortunate to be able to observe and study an old-growth beech forest in Germany— one of few original forests left in Europe. Suzanne Simard grew up observing the forests in British Columbia. After working as a forester, she became a professor involved in experiments to under-stand the ways trees communicate to help explain why lone trees and trees in monoculture tree plantations do not thrive like trees in a natural diverse forest.

In addition to explaining the “wood wide web” of tree roots and fungi, the narrators pose interesting questions like why are neighboring trees supplying sugar to keep a very old stump alive—does the stump from the ancient tree somehow possess knowledge that helps the nurturing trees? How do trees make fast decisions, like sending warning signals to other trees when predators attack? Are the roots possibly the “brain” of the tree, where such decisions are made? There is a similarity in structure and chemical transmitters that suggests this. The impact of clear-cutting and soil compaction from large logging machinery is described and alternatives like logging with horses are presented.

I think people tend to see trees as background to our needs and activities—they are not warm-blooded, they do not move around like we do, they do not seem to be feeling and caring like us. They are a resource for our needs. It is easier to exploit them if we do not see them as living beings. This film helps bridge the gap and aids us in understanding the true nature and intelligence of trees. Perhaps in time we will learn to support the forests in more sustainable ways.