Catalpa

Botanical name

Catalpa speciosa (northern or western catalpa)

Type

Fast-growing deciduous shade tree

Size

Large, with a fairly narrow, oval crown (Utah State University)

Hardiness

Zones 4 to 9; zones 6b to 7b here

Where it is found

Older yards on the valley floors, about 4,000 to 5,100 feet

Known weak points

Weak, brittle wood, verticillium wilt, messy pods

A catalpa is easy to spot in June and again in winter, when the long pods rattle in the bare crown. Utah State University says rarely should it be planted, though it does well throughout most of Utah. This page covers identification, where it grows in our elevation bands and when pruning or removal is right.

How do you identify a catalpa?

The leaves are among the largest of any yard tree here: heart-shaped, often longer than your hand, arranged in pairs or threes on the twig. In late spring the crown carries upright clusters of white flowers with purple and yellow spots inside. The fruit is a long, slender pod that looks like a bean and can hang on through the winter.

The shape is distinctive even without leaves. Utah State University describes a fairly narrow-crowned tree with an oval outline and coarse, crooked branches. Bark is gray-brown and scaly.

• Large heart-shaped leaves in pairs or threes
• White spring flowers with purple spots
• Long pods that persist through winter
• Coarse, crooked branches

Where does it grow in Reno, Carson City and the Carson Valley?

Catalpa is a tree of older valley-floor yards. USU rates it for zones 4 to 9 and high for drought and alkalinity, and says it is tough and tolerant of wet or dry soils. Reno (4,505 feet, zone 7b), Carson City (4,680 feet, zone 7a) and Minden (4,725 feet, zone 6b) are inside that range.

On the Nevada side of Tahoe, from Glenbrook (6,243 feet) to Incline Village (6,437 feet), hardiness is not the question; the shorter growing season, heavy snow and conifer-dominated lots are. We do not claim its elevation limit because the sources we read do not give one.

What goes wrong with it here?

Utah State University is blunt about the wood: somewhat weak and brittle, with branch breakage common. Large limbs on a mature catalpa can fail in a windstorm or under wet snow, and the pods and flower litter are a nuisance. See storm and snow-load breakage and what to do after heavy snow breaks limbs.

USU also lists verticillium wilt as a problem. It shows as sudden browning of leaves on one branch or one side of the crown. Drought can look similar, and so can root trouble, so the arborist checks before any conclusion; see drought stress and dieback. Catalpa is rated not good under power lines.

From the ground you can watch for a few things without touching the tree: limbs hanging lower than they did last year, a crack or seam where two big stems meet, fresh wood on the ground after a wind, and a patch of leaves that wilts and browns while the rest of the crown stays green. None of those proves a tree is failing, and none proves it is safe. They are the notes to give the arborist at the visit.

Pruning, cabling or removal: which is the right call?

Dead limbs and hanging stubs can be taken out any time of year. Structural pruning that shortens the longest limbs and removes crossing ones is best in late winter. The goal is a crown that sheds weight evenly rather than one that is thinned all over.

Cabling and bracing can keep a sound tree with a weak fork in service. Removal is the usual answer when the trunk is decayed, a limb has split at the union, or the crown has died back from wilt over a roof or driveway. Mature catalpas often need large tree removal, and tight yards may call for a crane.

What does Battle Born Tree Service do about a catalpa?

Start with a free estimate. A certified arborist assesses the tree before any work begins, and the estimate says whether the answer is pruning, cabling or removal. Two of our crew are ISA Certified Arborists, and credential WE-11728A belongs to one of them. We do not apply treatments for wilt or plant new trees.