Cheyenne Garden Gossip

Gardening on the high plains of southeastern Wyoming

Tough year for trees

2019-10 Lions Park--Barb Gorges

Cottonwoods need a lot of water, growing naturally along streams and lake shores. Sloans Lake in Lions Park, Cheyenne, Wyoming, photo by Barb Gorges.

2019’s top horticultural questions in Laramie County include trees and prairie

By Barb Gorges

The phone calls Catherine Wissner gets are a good snapshot of what is going on in Cheyenne yards. She is the University of Wyoming Extension horticulturist for Laramie County.

When gardeners or property owners notice something amiss with their crops, landscaping or houseplants that they can’t figure out, Catherine gets their calls and will often visit. I asked her what the most frequent topic was this summer.

Trees and fungus

“Trees,” she said. Mistreat a tomato plant and you don’t get tomatoes. Mistreat a tree and you lose a major financial investment when it either dies immediately, or lingers for years, looking stunted and unhealthy.

This year, we can blame the weather for a lot of tree problems, Catherine said. April through June we had nearly as much precipitation as our annual average, 12-15 inches. All that moisture aided the growth of fungus.

The most common was verticillium wilt. It’s in the soil and gets into trees, shrubs or other plants through the root system. Damaged roots are most susceptible. Sprays and injections don’t work on fungus.

The fungus moves from the roots through the tree’s vascular system (think sap instead of blood) and within a week of showing signs of stress, the tree is dead.

Some tree species or varieties are more resistant, Catherine said. You must do your homework when looking for a replacement tree. But don’t plant the new tree in the same place.

2019-10 oak--Barb Gorges

Due to a wetter than normal spring, fungus affected these oak leaves. It’s mostly a cosmetic problem, not life-threatening. Photo by Barb Gorges.

Another fungus affects oak leaves, leaving brown splotches. Just clean up the leaves when they fall off. Next year the trees may not be affected.

2019-10 pine--Barb Gorges

Without intervention, this type of damage to the tips of pine branches will eventually kill the tree. Photo by Barb Gorges.

Pines can be attacked by a tip-boring insect—it bores into the tips of branches causing them to look lumpy. Because she values pollinator insects and birds, Catherine recommends pesticides as a last resort. In this case, without using a systemic pesticide like Safari, absorbed through the trunk or as a soil drench around the trunk, the tree will be lost.

Get Catherine’s advice before choosing a pesticide. Read the directions and avoid methods that could blow the toxins onto other vegetation and animals.

Trees and drought

July through most of September we had no rain to speak of. Trees depend a lot on the roots in the top 1 to 2 feet of soil—and out much further than the reach of their branches. Many of the trees planted in Cheyenne are not drought tolerant, including cottonwoods which in nature grow along streams.

This year, many people in my neighborhood seemed to be saving money by not watering their lawns during those droughty months. That’s fine if the grass only goes dormant. If it dies though, the noxious weeds will move in.

No lawn watering means trees that are not drought tolerant start losing leaves prematurely and become victims of stress and disease. Catherine pointed out that watering your mature spruce tree is cheaper than the $1500 it would cost to have it removed if it dies.

This fall, and warm winter days once a month, is the time to make it up to your trees. Water your whole lawn if you have mature trees.

Late fall and winter are also the best times for tree pruning.


2019-10 WHR--Barb Gorges

The shortgrass prairie outside Cheyenne, Wyoming, doesn’t need mowing. Photo by Barb Gorges.

Prairie problems

People moving to acreage and unfamiliar with the prairie are smart to contact Catherine for basic instruction.

The worst thing to do to the prairie is mow it. But do mow the patch of bluegrass lawn the kids play on and the firebreaks immediately around the house and along fence lines.

Unmown prairie benefits you and provides bird habitat–grassland birds nest on the ground. Grasses shade the ground and keep it cooler and they will trap snow, giving it a chance to melt and sink in. Cooler ground is less likely to burn.

Mowed prairies encourage warm-season grass species at the expense of cool-season species which keep the prairie cooler.

Don’t mow the thistles! It encourages rhizomes, underground stems, to spread and pop up more plants. Catherine said to spray the individual plants when they are blooming or after the first frost. Thistle is a tough, non-native invasive plant that requires tough measures.

Catherine makes yard calls for free or you can bring in a diseased twig (in a sealed plastic bag) to her. You can also email photos to her.


Laramie County Extension Office

Catherine Wissner, 307-633-4383,

Trees and all other plants.

Cheyenne Urban Forestry Division

Tree species recommendations, planting and maintenance instruction, city tree ordinances, certified arborist list.

Laramie County Conservation District

Clark Young and Dale Beranek, 307-772-2600.

Trees, especially windbreaks.


What I’ve learned as a Master Gardener

2018-08Garden tour-Barb Gorges

Outside Ft. Collins, Colorado, one woman, over 20 years, has created a garden refuge. Photo by Barb Gorges.



Published Aug. 12, 2018, in the Wyoming Tribune Eagle and at Wyoming Network News,

By Barb Gorges

This is my seventh season as a Laramie County Master Gardener (and Wyoming Tribune Eagle garden columnist). I know more now than when I finished the training because there’s always someone to talk to who knows more than me about any aspect of gardening.

I’ve interviewed many people, including other Master Gardeners, for previous columns which are archived at Here’s what I’ve learned:

Always evaluate gardening information. Where does that gardener garden? Is it a garden with a similar climate or microclimate, soil and growing season to mine? Will the treatment harm my soil?

There’s a difference between sticking stuff in dirt and growing plants with more mindfulness—and record-keeping.

You can grow many things in Cheyenne, but not all things. Just keep experimenting with the short-season veggies and consider building a greenhouse or high tunnel.

Cheyenne’s blooming season is longer than you think. In my garden some spring bulbs bloom in March. Some years the frost doesn’t finish the asters until the end of October.

Garden beauty is subjective but good garden design is practical:  put short plants in the front of beds, veggies by the kitchen door and don’t plant trees under power lines.

Every growing season is different. Not every year has powdery mildew, black spot or blossom end rot.

Know when to give up. Or try the plant in a different location. Or try a different variety.

Gardeners are generous. They share plant thinnings and seeds because they can’t bear to compost them.

Propagation from root divisions, cuttings and seeds is rewarding, especially when you share.

Never add lime, an alkaline substance, to Cheyenne’s already alkaline soils.

Gardeners like a challenge, even as extreme as planting acid-loving blueberries in buckets full of specially mixed acidic soil.

Soil is every gardener’s most valuable asset. Preserve its structure and microbiome by tilling and hoeing as little as possible and let mulch keep the weeds down.

Composting your discarded plant material in your own bin or pile saves you money on fertilizer and the cost of having the sanitation department haul it away.

Getting watering and mulching right is more important to plants than fertilizer.

Good pruning benefits trees and shrubs by making them look good and grow better.

Right plant in the right place—not all trees are growing in the right place.

Hail is a fact of life here. Protect tomatoes with hardware cloth screen overhead and grow skinny-leaved and skinny-petalled flowers.

Replacing your lawn with gravel is not less work in the future. It gets weedy. And gravel doesn’t shade the ground, which makes your yard hotter. You are better off with a low-growing ground cover.

Chemical pesticides are rarely necessary in the residential garden. You can pick off pests and remove diseased plant parts by hand.

Stressed plants (too much or too little water, too much fertilizer, too much or too little sun) attract disease and pests.

The sooner you pull a weed or cut it off at ground level, the less work it is later.

Always take care of weeds before they set seed.

Tending a garden is stress-reducing. Many of the gardeners I’ve interviewed have high stress jobs: lawyer, judge, law enforcement, social worker, doctor.

Gardening is good exercise. Even if you aren’t vigorously digging a new bed, just walking around pulling the occasional weed and deadheading the roses is better for you than sitting.

Gardeners see more bees, butterflies and birds—just more of nature.

Visiting botanic gardens when you travel makes for beautiful memories.

Reading to prepare for and dreaming about next year’s garden will get you through a long winter.

Want to start gardening or garden more intentionally and with more knowledge? Become a Laramie County Master Gardener. It’s not too early to find out about the next class. Call Catherine Wissner, Laramie County Extension horticulturist, 307-633-4383.

2018-08 Asters Snowy Range 7-18 Barb Gorges

Asters bloom and attract a bee in a natural rock garden July 18, 2018, in the Snowy Range in southeastern Wyoming at an elevation of 9,000 to 10,000 feet. Photo by Barb Gorges.

Pruning Trees and Shrubs


Pruners: The no-brand-name ones made in Japan have lasted the longest.

Published Feb. 17, 2013, in the Wyoming Tribune Eagle, “Train a tree for the future: Winter is the perfect time to prune trees. But you’ll want to keep these tips in mind before you start snipping.”

By Barb Gorges

“Train up a tree in the way it should go; and when it is old, it will not depart from it.” –adapted proverb

Pruning a young tree may not be for the faint of heart.

I wasn’t sure Michael Smith wasn’t sucking in his breath as Catherine Wissner lopped off a nearly 1-inch-diameter, 4-foot long, competing leader on one of his cherished young aspen trees.

While making arrangements for Smith, photo editor for the Wyoming Tribune Eagle, to take pictures of pruning techniques for this story, he volunteered the trees in his yard for a house call from Wissner, the horticulturist for the University of Wyoming Laramie County Extension. And he did have perfect examples of several situations requiring pruning.

Surprisingly, winter is the best time for pruning most trees.

“You can see their bones,” Wissner said.

You can see all their structural, health and safety problems.

Being a season for dormancy for trees as well as insects and diseases, those problems are less likely to spread through the fresh cuts. Also, if you need to hire an arborist, he or she may not be as busy.

Millions of wild trees are pruned by nature, but on your own property, you really don’t want to wait for the wind to do it for you, dropping a weak limb onto your car or onto your roof.

Arborists are trained to recognize a variety of situations, but there are a few that you can easily recognize and take care of while trees are young, which will save you (or the next homeowner) money and heartache a decade or two in the future.

But first, let’s talk about how to cut. There are three caveats.

pruning saw

Pruning saw with broken tip

How to cut

First, make sure your tools are sharp and sanitary.

If you are cutting away diseased wood, be sure to disinfect tool blades after each cut. Wissner uses ¼ cup bleach to a gallon of water. Follow that up with a clear water rinse to keep the bleach from corroding the metal.

Hand pruners work for twigs and branches under 1 inch in diameter. Wissner prefers the bypass type (scissors-like) rather than the anvil type. A pruning saw is best for anything more than an inch. Bow saws are fine too, but can be hard to get into position without damaging nearby branches.



Keep in mind chainsaws are likely too big for the job when it comes to young trees. You could end up doing some serious damage.

Second, never remove more than 25 percent of the tree’s canopy in one year. Err on the side of less, rather than more pruning.

Third, cut in the best place. Every twig and branch emerges from a collar-like protrusion. Your job when removing them is to make sure that the collar is not damaged while you cut as close to it as you can. It is what will help the tree “cork over,” or grow bark over the wound, said Wissner. (No wound dressing is necessary on a fresh cut of any size— it’s been shown it only attracts insects and disease.)

On the other hand, she said, “You shouldn’t leave anything you can hang your hat on.”

When shortening a branch, cut at an angle just above the juncture with a bud, twig or side branch.

 No touching

The first rule of pruning is no touching. Look for branches that are rubbing on each other or are within a fraction of an inch apart and will rub in the wind.

“It’s like a school dance,” said Catherine, “and you are the chaperone. They aren’t allowed to touch.”

Branches that touch will rub each other’s bark away, leaving wounds that are easily infected by tree diseases and insects. You could eventually lose both branches.

Instead, you can determine which branch to keep: the one that is stronger and or contributes best to the shape you want the tree to grow in.

The no touching rule also applies to human structures. You don’t want branches rubbing on your house or fence—it’s bad for the tree and the object. Branches should be trimmed 4 feet above roofs so that there is plenty of clearance when they are snow-laden.

As for public safety, city ordinances require removing vegetation 8 feet above sidewalks and 14 feet above alleys and streets.

Only one leader

Everyone recognizes the pointy top of a spruce tree is its central growing point, which arborists refer to as the leader, but even most deciduous trees should have only one.

However, when I look at the 50-plus-year-old trees at my house, it’s easy to see that accidents caused the trees to produce multiple leaders.

One of Smith’s young aspens had the same problem. You could see the original, now dead leader pointing perfectly vertically to the sky, but on either side were two lateral branches now also pointing up, competing for the job.

Left to their own devices, the leaders use the tree’s valuable energy competing with each other. Only the healthiest, best looking one should stay. The tree will be happier, said Wissner, when it can devote its energy to just one leader.

Branches never grow up

The height of where a branch attaches to the trunk never changes as the tree ages, Wissner told us.

One of Smith’s aspens had lateral branches at about two feet above ground level. As the tree grows, they will only get bigger and begin to become obstacles while mowing the lawn. He could mulch around the tree, so mowing close wouldn’t be necessary. One thing for him to consider is that some branches might still be at the eye-level of his children playing in the yard.

On the other hand, spruce trees should be left to drape their branches to the ground (that much less lawn to worry about!). It helps if they are planted where their branches don’t interfere with human activity when they are at their mature spread of as much as 30 feet across.

Get the suckers

A tree may send up a sprout, or sucker, from the roots, or water sprouts on a main branch. They can grow as much as three or four feet in one year, with leaves larger than normal for the tree. These are a drain on the tree and increase its chances of acquiring disease, so they should be loped off immediately. They usually die back in a year or two anyway.


Even in winter, dead branches in a deciduous tree are pretty obvious. Compared to live young branches, the leaf buds aren’t plump, the skin looks desiccated and the branch is no longer as flexible.

If you are removing diseased wood, cut in healthy wood beyond the infection.

Volunteer trees

It will surprise people to know that there are a fair number of trees that plant themselves in Cheyenne.

The volunteers usually pick a microclimate with a bit of extra moisture or shade, like right next to your house foundation. Roots are stronger than concrete so you are best off removing those trees before you get attached to them. However, the trees damaging Smith’s fence–some kind of flowering plum–were probably planted too close.

Volunteers are usually softwood trees that don’t last long in Cheyenne anyway, such as silver maple, elm, boxelder, poplar and willow, and are the most likely to shed limbs during storms.

Seek expert advice

Trees add value to your home, but only if they are healthy and not threatening people or property. You can do a lot for them yourself with a hand pruner when they are young, but get more information if you have fruit trees and please call certified arborists for the big issues and big trees, especially if utility lines are involved.

The best information about our local trees and taking care of them is at, the Cheyenne Urban Forestry Division’s website. They have a list of licensed arborists. You can call them at 637-6428.

The Arbor Day Foundation website has a nifty animation of the finer points of pruning young trees, It is also available in print from the Urban Forestry Division.

And Catherine Wissner can be reached at 633-4383.