Thin Air Harvest Practical gardening for the high, dry West

Plants

Trees that face alkaline soil, wind, and winter sun

Why maples and pin oaks yellow on Western soils, which trees have a better record, and how to plant them so the root flare survives.

By the Thin Air Harvest editorial team. Updated November 1, 2026.

A tree is the most expensive plant in the yard and the slowest mistake to undo. On the calcareous soils common along the Front Range, the Wasatch Front, and much of the high plains, the mistake is usually a species that cannot take the pH, planted too deep, and then watered like a lawn.

Colorado State University Extension’s iron chlorosis fact sheet describes the symptom and the short list of causes. New leaves yellow between green veins. Soils high in lime hold pH above 7.5 and tie iron into forms the roots cannot use. The soil often has plenty of iron.

Adding more, without changing the plant or the conditions, repeats the chemistry. Overwatering and compaction make it worse. Winter injury and chlorosis feed each other, because a weak tree is easier for winter to damage, and a damaged tree shows chlorosis more readily.

PlantTalk Colorado names the trees people keep planting anyway: red and silver maples, Amur maple, pin oak and other red oaks, aspen, and many fruit trees. The longer CSU table adds birch, honeylocust, and a range of conifers and shrubs. “Honeylocust is tough” is only half a sentence in this soil. It is tough about some things and yellow about iron. Read the table before you repeat a street-tree fashion from 1995.

A shorter list with a better record

No tree is immune on compacted, overwatered clay. These are trees that fail less often on alkaline ground when the planting is competent.

Bur oak (Quercus macrocarpa) is not a Front Range native and has a long record as a plains and Front Range shade tree. Give it room.

It is a large tree. Gambel oak (Quercus gambelii) is the native oak of the foothills and Utah benches, smaller, sometimes a thicket. It belongs where a thicket is acceptable.

Hackberry (Celtis occidentalis) handles heat, wind, and alkaline soil and feeds birds. The fruit is messy on a patio. Put it in the yard, not over the deck.

Kentucky coffeetree (Gymnocladus dioicus) is another large, open shade tree with a good alkaline record. It leafs out late, which looks like death in May and is the species in June. Plant a male if you do not want pods, and ask the nursery which you are getting.

Rocky Mountain juniper (Juniperus scopulorum) is a regional native tree for screens and wind, not a plant for a sprinkler-soaked lawn. CSU’s susceptibility table includes “juniper” as a group, which is a reminder that some junipers chlorose and that arborvitae, often sold beside them, burns in winter wind. Species and site still matter. A native juniper on a dry slope is a different plant from an eastern arborvitae against south-facing siding.

Pinyon, ponderosa, limber pine, and bristlecone belong in the elevations and soils where they already grow. Pinyon in a lawn in a cold mountain valley is the wrong pine and the wrong water. Ponderosa wants space and will not stay a foundation shrub.

Serviceberry and chokecherry are small trees or large shrubs with a native record and a fruit use. They are on the small-fruit page.

Fruit trees can be worth growing and can still yellow. Apples are on the susceptible list. If you want the crop, plant the apple in the best-drained spot, do not overwater it, and accept some chlorosis management. If you want shade, plant the oak.

Planting so the tree can use the soil it has

Dig a wide hole, at least two or three times the width of the root ball, and no deeper than the ball.

The root flare, where the trunk widens into roots, sits at or slightly above the finished grade. A tree planted in a deep pit in clay becomes a tree sitting in a bucket.

Water collects, oxygen disappears, and chlorosis or rot follows. Do not amend the backfill into a soft pot of compost surrounded by hard clay. Roots will circle. Set the tree in native soil, water it, and mulch the surface.

Mulch two to four inches deep, pulled back from the bark. A mulch volcano is a vole and rot factory. Stakes, if you use them at all, are low and loose, removed after a season or two.

A rigid stake makes a weak trunk and then snaps the tree at the tie in a Front Range wind. The wind page covers that.

Water is a basin, widened each year, deep and infrequent, for two or three summers. Then less, unless the tree is a species that will always need irrigation in your rainfall.

A daily sprinkle from the lawn system is the wrong life. It grows shallow roots and cold, wet soil. Split the valve.

Winter sun and chinooks

Thin-barked young trees sunscald on the south and southwest side in winter, when a bright day warms the bark and a night freeze splits it. A white trunk guard or a spring-removed wrap on the young trunk is ordinary protection for the first winters.

Take fabric wraps off during the growing season so insects do not live under them. A chinook climate makes this worse, because the temperature swing is larger. Evergreens placed against a reflective south wall lose water from foliage while the ground is frozen.

University of Idaho’s harsh-climate bulletin describes that exposure as a help to vegetables and a risk to woody evergreens. Put the spruce or the fir where it is not against the hottest wall, and water it in fall so it enters winter hydrated.

Do not fertilize a newly planted tree “to help it along.” Fertilizer is for a deficiency a soil test or a foliar symptom has identified, not for planting day. A chlorotic maple does not need nitrogen. It needs a different species, or a specific iron treatment with the limits described in the soil test article.

Checklist

A tree is also a hail and wind object. A young tree shredded by hail usually releafs if the wood is intact.

CSU’s hail notes say to prune hanging damage with clean cuts, skip the fertilizer, and water during drought. Do not paint the wounds with tar. Do not top the tree.

Sources