Catalpa, a shade tree with amazing orchid-like blooms

Mature Catalpa tree

Catalpa is a true garden-enhancing tree thanks to its unique foliage, especially in fall.

This fast-growing tree is also very hardy in winter.

A summary of key Catalpa facts

NameCatalpa
FamilyBignoniaceae
Type – Tree

Height – 26 to 32 feet (8 to 10 meters)
Exposure – Full sun
Soil type – ordinary

Leafage – deciduous
Blooming – June-July

How to plant catalpa

Catalpa is an easy tree to grow. It will settle in properly in any type of soil, even though, as for most trees, it prefers well-draining soil.

This tree loves sunlight, which makes it an excellent shade tree.

  • Note that in winter, it fears excess water.
  • Favor planting your tree in fall to promote root growth before the winter frost spell set in.

Pruning and care for Catalpa

Pruning Catalpa

Any shade will make the tree grow taller instead of wide.Remove lower branches to keep them from reaching the ground.

Catalpa starts growing with a thin, upright figure that tends to round off with age.

  • Make sure the tree has plenty of space to grow.
  • The natural shape will always be taller than it is wide.

Watering your Catalpa

In summer, water well during the first 2 or 3 years if the weather is hot.

  • After that, no need to water.

In dryer areas, mulch the tree around the trunk and all the way to where midday sun lays shade.

  • This is called the drip line, and it’s where roots are most active.
  • Mulch provides them with needed nutrients and moisture.
  • Mulch will help avoid leaf scorch during particularly hot and dry summers.

Catalpa diseases and pests

Three main diseases may affect a weakened Catalpa tree. These are all fungal diseases.

Verticilium wilt on Catalpa

Verticilium wilt – Often fatal. Purple-gray streaks appear on wood when a branch is snipped. Leaves wilt, usually along an entire branch or along the sap-flow to one side of the tree.

  • Using high-nitrogen natural fertilizers is a great help to help your catalpa fight the fungus off.
  • A growth spurt might succeed in “burying” the fungus under new wood.
  • This is because the fungus has trouble crossing over radially through wood. It prefers spreading up and down along the tree.

Powdery gray or white dust on Catalpa leaves

  • Powdery mildew – As may appear on oak trees in warm, moist weather. Dusty white powder appears leaves near leaf veins.

Spots on Catalpa leaves

Leaf spot – Many possible culprits here. Usually the main fungus is Anthracnose, caused by Gloeosporium catalpae, but others also may appear.

Learn more about Catalpa

Catalpa is a wonderful tree thanks to its blooming shown in the picture below.

  • The flowers are very surprising for such a tall tree. They’re similar to those of orchid or iris.
  • It’s also very much appreciated for its cool, breezy shade.

Spectacular and abundant flowers appear in June, signaling the time to start taking advantage of the shelter Catalpa provides from scorching heat.

Growth is rapid, and will speed up even more if planted in a warm spot.

Smart tip about Catalpa

During the first few years, spread some mulch at the base of the tree to stimulate its growth.

Several orchid-like flowers of the catalpa tree

Catalpa on social media

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Picture related to the article overlaid with the Instagram logo.

Credits for images shared to Nature & Garden (all edits by Gaspard Lorthiois):
Catalpa full tree by Ross Dunn ★ under © CC BY-SA 2.0
Upright Catalpa by Catherine Fraser ★ under © CC BY 2.0
Flower of the catalpa tree (also on social media) by Светлана Бердник ★ under Pixabay license