Tree with bean pods

Northern catalpa

Northern catalpa (Catalpa speciosa) photo: John Hagstrom

Size & Form

A large, upright to rounded tree reaching 50 feet high and 35 feet wide.

Tree & Plant Care

Best in full sun in well-drained soil.
Tolerant of temporary wet conditions but should not stand in water.
It is very adaptable to adverse conditions but is pollution sensitive.
This tree can be messy when flowers and fruits fall; branches are brittle and may fall in storms.

Disease, pests, and problems

Verticillium wilt and minor problems like leaf spots and powdery mildew.

Native geographic location and habitat

Native from the lower Midwest into the southern states (southern Illinois south to Arkansas).

Bark color and texture

Bark is gray-brown, scaly with age.

Leaf or needle arrangement, size, shape, and texture

Simple leaves are 6 to 10 inches long and heart-shaped, whorled or opposite along branches. Fall color is yellow-green to brown.

Flower arrangement, shape, and size

Upright, 4 to 8 inch clusters (panicles) of white, bell-shaped flowers with orange stripes and purple spots and stripes.

Fruit, cone, nut, and seed descriptions

Pod-like capsules, 8 to 20 inches long, filled with winged seeds.

Cultivars and their differences

Heartland Catalpa (Catalpa speciosa ‘Hiawatha 2’): 50 feet high and 25 feet wide, upright, narrow oval

Bean Trees

Though its fruit capsules look like long beans, northern catalpa (Catalpa speciosa, 2776-B) is not a member of the pea family. Photo by William (Ned) Friedman

This common honeylocust (Gleditsia triacanthos, 14681-A) displays the pod fruits typical of the pea family (Fabaceae). Photo by Nancy Rose

As my vegetable garden winds down for the year, I am, as usual, astonished by the productivity-per-square-foot of the bush green beans. Green beans (Phaseolus vulgaris) are part of the pea family (Fabaceae), a large and diverse group that includes many economically important plants (e.g., soybeans, peanuts, alfalfa) as well as lots of choice ornamentals. Many of the nearly 20,000 species in Fabaceae (also known by the older family name Leguminosae) have a symbiotic relationship with soil bacteria that fix nitrogen in nodules on the plants’ roots, which can allow the plants to grow in nitrogen-poor soils.

Japanese pagoda tree (Styphnolobium japonicum, 1239-83-C) bears loads of typical “pea flowers” in late summer. Photo by William (Ned) Friedman

The Arboretum collection holds over 300 plants within 19 genera of trees, shrubs, and vines in the pea family. Like my green beans, many have classic “pea flowers” including the lovely wisterias (Wisteria), fragrant black locust (Robinia pseudoacacia), and late-blooming Japanese pagoda tree (Styphnolobium japonicum 216-35*A). Others have very different looking flowers, like the pink, powderpuff-like blooms of silk tree (Albizia julibrissin ). You’ll notice the family ties more, though, when you look at their fruit: typically an elongated, single-chambered pod containing a number of individual seeds.

All those dangling pods might make you think “bean trees” but, oddly, the species at the Arboretum that do sometimes go by the common name “bean tree” aren’t even in Fabaceae. Catalpa speciosa, best known as northern catalpa, and its North American relative, the southern catalpa (C. bignonioides), are also known as bean tree, Indian bean tree, or cigar tree for their prominent clusters of long, narrow fruits. Botanically, these podlike fruits are actually capsules that contain many fringed seeds. Catalpas are members of Bignoniaceae, a family also represented at the Arboretum by several vines including trumpet creepers (Campsis spp.) and crossvine (Bignonia capreolata).

The Northern Catalpa Tree

An astonishing mountain of white blossoms covering a huge tree beside an old Victorian farmhouse stopped me in my tracks on a beautiful day early in June. I pulled the car over to take photos. For the past 25 years I never noticed the stunning blossoms of this nearby Catalpa tree! This curious tree with its almost tropical show of speckled white flowers, looks out of place in New England; too showy for our Puritan tastes.

The elegant trumpet shaped flowers are clustered on panicles (stems) in tiers with three smaller stems. The first two tiers produce three flowers at the end of these smaller stems to add up to nine individual flowers per tier or 18 flowers on the two tiers. The lower tiers have but one flower at the end of the smaller stem or six additional flowers. There were 24 individual flowers on the cluster that I counted. The big round buds burst open like popcorn kernels revealing the wadded up flower inside. Miraculously, the delicate flower tissue unfolds without a wrinkle and the frilly scalloped petal edges unfurl perfectly. The flowers look as if they were individually painted with two deep yellow stripes leading to the flower center with purple speckles and markings completing the decoration; all to attract pollinators. Somehow the seeds produced by the flowers end up inside long skinny 6” -12“ beans that dangle from the tree later in the summer; hanging on through the winter.

Catalpa trees are designed for survival. Not only are they loaded with flowers, they are dual pollinated, both during the day and also at night! Bees pollinate the flowers in daytime, guided by the yellow and purple markings (nectar guides). At night, increases in nectar and fragrance attract moths to continue the pollination process. (haverford.edu/Arboretum/files/summer2009.pdf).

The huge, broad leaves with netted veins are a medium green and almost lustrous in the sunlight. The underside is lighter green, soft and fuzzy. The edges are smooth. Of course these huge leaves cast dense shade so not much grows under the tree. If not pruned, the branches droop to the ground.

Catalpa trees are an imported species to New England and thought to be native to the mid-west from Arkansas to Indiana. Another species of catalpa, caltalpa bignoioides is native to the south and is not quite as large or as hardy as Northern Catalpa or C. speciosa. The huge old caltalpa trees sprinkled throughout NH are evidence that it is a tough tree that can survive our harsh, cold climate. It was brought north as an ornamental and popular in the Victorian era where it complimented the grand Victorian estates.


Seed pod (6-12″ long), which gained this tree its nickname The Cigar Tree

The Catalpa grows quickly and needs a large sunny lawn where it can flourish. It is tolerant of many soil types including compacted soils, and grows well along roadsides and near pavement. Its wood is brittle and it can break in wind storms. In spite of its toughness, it is uncommon in NH today, and the few large trees when seen in full flower are showstoppers. A friend explained to me one reason it is uncommon. It is a very messy tree; always shedding twigs and branches, then dropping all those blossoms, followed in the fall by the huge leaves, and finally the litter of the long, cigar-like seed pods (it is also called cigar tree) that drop in the spring. Another negative feature is that it drips sticky residue onto cars parked underneath, an excuse for some to cut them down. Another reason it is uncommon is that its wood makes excellent posts and railroad ties, so they were harvested for these uses, eliminating seed sources. That may not be all bad, as catalpa is included on invasive lists for some states. Huge flower production means huge seed production.

The NH state champ Catalpa tree is in Epsom, Merrimack County, is 62 feet tall with a trunk diameter of 190 inches. To join in the hunt to find NH’s biggest trees, please visit www.nhbigtrees.org.

By Ellen Barcel

There are two trees commonly seen on Long Island that look very much alike. They are both quick growing trees, with large heart-shaped leaves. Both have taproots. The major difference to the casual observer is that one has purple flowers in spring while the other has white flowers in early summer. The purple-flowered tree has round seedpods and the white-flowered tree has long string-bean-type seedpods.

Initially, many, many years ago, I assumed they were related, perhaps different varieties of the same tree. Wrong! What are these similar trees? The Royal Paulownia tree and the Catalpa tree.

Royal Paulownia Tree
Let’s start with the Paulownia (Paulownia tomentosa), also called the Empress tree and the Princess tree. The tree is a native of China and is extremely fast growing and a prolific producer of seeds. It is considered to be an invasive species, being brought to North America when the seeds were used as packing material for goods shipped from Asia. The seeds quickly took root and the tree has naturalized in North America. The wood of the Paulownia is used extensively in Asia for a variety of things.

Many people believe that it is an invasive plant, one that grows very quickly and therefore takes over forcing out the native species. As a result, it is listed on Suffolk County’s Management List of Invasive Species. It is recommended that it not be planted on Long Island especially near or on public land (see last week’s gardening column for details on the management list).

The purple flowers of the Paulownia tree come out before the leaves. Its bare branches and an evergreen tree can be seen in the background. Photo by Ellen Barcel

However, I recently came across several references to an article by Charles J. Smiley printed in the American Journal of Botany (1961) that the tree was actually native to North America as fossil leaves have been found from Washington State as far back as the Tertiary Period (66 million to 2.6 million years ago) and may have subsequently gone extinct here. Obviously, there is some disagreement among experts as the tree is still listed as invasive by a number of sources, including the New York Invasive Species Clearing House.

The American Paulownia Association can be reached at www.paulowniatrees.org. The group was “organized and developed through the joint efforts of the University of Tennessee and the University of Kentucky Extension Services” in 1991 and dedicated “to the advancement of Paulownia as a forest crop in the United States.”

The Paulownia prefers sun, grows in virtually any type of soil, is somewhat drought tolerant and does well in U.S. Department of Agriculture’s Hardiness Zones 5 to 11 (Long Island is 7). It has no significant disease or insect problems. The tree will even resprout from the root if cut down (remember that taproot), can reach heights of 70 to 100 feet and is long lived, reportedly from 60 to 100 years.

Catalpa Tree
The other tree, the Catalpa, is definitely native to North America. There are basically two varieties, northern (which grows here so well) and southern (which does well in warmer climates). Like the Paulownia, the tree is deciduous, losing its leaves in fall — quickly. In fact, it is one of the first trees to lose its leaves in fall.

The flowers of the Catalpa appear in late spring or early summer (mid-June this year) and resemble tiny orchids — white with purple throats — after the tree has leafed out. Like the Paulownia, the tree can reach a great height, easily up to 60 or more feet tall. The Catalpa grows well in hardiness zones 4 to 8. It does well in very acidic to neutral soil, pH 5.5 to 7.

The tree can be very long lived, reportedly 60 to possibly up to 100 years of age. One of mine died after about 25 years having been struck by lightning but did resprout from the root. Anthracnose (a fungal disease of some hardwood trees) can attack the leaves during very humid weather, but the tree itself usually survives quite well.

Because of its potential age, quick growth rate and hardiness, it makes a great shade tree. However, if you’re looking for autumn color, it will not provide it.

Ellen Barcel is a freelance writer and master gardener. To reach Cornell Cooperative Extension and its Master Gardener program, call 631-727-7850.

I’d like you to meet one of my favorite trees, the Northern Catalpa Tree. Its rich history and botanical legacy are unique and fascinating.

I’m getting to know my backyard neighbors!

As hard as I try, I can’t figure out any way to become the knowledgeable naturalist I want to be except by reaching out to meet my nature neighbors one at a time. Identification is the first step, but when I dig a little deeper to learn more about each of these living creatures, I gain not only knowledge but a deep affection and appreciation for their unique features and their history. Today I want to introduce you to my catalpa tree.

Meet Catalpa speciosa, the Northern Catalpa Tree

The catalpa blossom

Right now, in early June, the catalpa tree in my yard is in full bloom, and what a magnificent sight it is! “Thousands of flowers on an old catalpa tree look like a colossal chandelier of bulging, white foxglove-like blooms, spotted inside with purple and yellow,” describes writer Allen Bush, and he’s exactly right. The sweet fragrance rivals that of honeysuckle, and its showy blossoms make the catalpa trees easier to spot than they are any other time of the year. I was amazed today how many catalpa trees I noticed in yards and woods along the highways and byways here in Shenandoah County, Virginia.

Note opposing leaves and heart shape

Besides the blossoms, the catalpa’s leaves and fruit are also unique. Its leaves are large and often compared to elephant’s ears or large hearts. They can grow up to 12 inches long and eight inches wide, emerging from the branch directly opposite each other. The catalpa fruits are long, hanging pods up to 18 to 20 inches in this species. They’re green early in the summer, but they eventually change to a dull brown, hanging onto the trees through winter until opening in the spring to release their seeds. My lawn-mowing husband says they’re hard on the mower blades, so he tries to rake most of them up before mowing.

This marvelous tree has long been a favorite of mine (but don’t tell the Canada Maple tree, who thinks she’s my favorite. I’m fickle that way.). At 80-90 feet high, it towers over most of the other trees in my yard and must be quite old, because its diameter is four feet and its circumference is over 12-1/2 feet (yes, I dusted off my geometry formulas to figure the diameter from measuring the circumference with a piece of string). This species can grow to 100 feet high, but it averages between 60-80 feet, so I clearly have a marvelous specimen! The largest living catalpa tree in the world is said to be the one on the grounds of the Capital of the State of Michigan in Lansing. It was planted in the year of its dedication in 1879 and is 60 feet high and seven feet in girth. Since mine is larger in both height and girth, I wonder if I should contact someone about seeing if mine might hold a record. NOTE: After first publishing this post, I learned that the catalpa tree in Michigan is no longer the largest on record. That claim is now held by a tree in Indiana which sounds like it’s bigger than mine: http://www.americanforests.org/bigtree/catalpa-speciosa/.

The oldest catalpa tree is thought to be in England. Some sources claim it is a tree in Rochester at the foot of England’s second oldest cathedral (“The Rochester Catalpa”), but others say it’s the specimen in the Minster graveyard of St. Mary’s Butts in the town of Reading, Berkshire. I was unable to corroborate either claim.

A catalpa by any other name…

My tree, it seems, has many nicknames. Many believe the word “catalpa” is a misspelling by an early botanist of “catawba,” the Native American (Seminole) name for the tree, and indeed it is still called a catawba tree, especially in the South. That’s the name my Louisiana-born husband knew when he was growing up. Other names based on its conspicuous fruit/bean include Indian Bean Tree, Cigar Tree, and Cigarette Tree.

Catalpa tree trunk with mysterious hole.

What about the worm?

Two other nicknames, Worm Tree and Fish Bait Tree, come from a hungry caterpillar called the Catalpa Sphinx, a.k.a. the catalpa worm, that loves to feed on catalpa foliage. It is greenish yellow with black lines and markings. These caterpillars are greatly prized as fish bait, and I remember as a child hearing of anglers who paid kids to fill jars with these prized caterpillars or “worms.” I read they can be preserved alive by freezing them in an airtight jar filled with cornmeal or “pickling” them in a jar with corn syrup (see Nix below), but I think I’ll pass on that activity. I don’t recall seeing them on my tree here. Apparently, infestations don’t necessarily occur every year, but when they do, the caterpillars are capable of stripping the tree of its leaves, supposedly without long-term damage to the tree.

Let’s get technical

The catalpa tree is a genus of flowering plants in the family Bignoniaceae. They’re native to warm temperate regions of North America, the Caribbean, and East Asia.There are two North American species, and the one we have here in Virginia is Catalpa speciosa or Northern Catalpa. The other is Catalpa bignonioides or Southern Catalpa. This tends to be smaller than its northern cousin. Worldwide there are as many as eleven species of catalpa. Its first English notation is thought to have been by Mark Catesby in about 1731 in his book The Natural History of Carolina, Florida and the Bahama Islands. So there you have it.

I confess to some concern after learning that my catalpa may be close to the end of its life expectancy, but if she has the same longevity as the oldest specimens on record, she’ll still outlast me. Do you have a catalpa tree in your yard?

My Backyard Nature challenge

I challenge you to select a favorite tree in your yard or neighborhood and get to know it. If you don’t know its identity, ask around. Or take a specimen of the leaf to your nearest Master Gardener, Extension Office or nursery. Then do a little research, notice its changes over the four seasons, and before you know it, you and your tree will be old friends.

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RESOURCES

Bush, Allen. “In Praise of the Humble Catalpa.” Garden Rant: Uprooting the Garden blog. May 8, 2012.

Catalpa Tree Facts. GardenGuides.com.

“Catalpa.” Wikipedia.

Gladden, John. “The Big Tree contest: Northern Catalpa is subject of annual challenge.” The Medina-Gazette Online, May 10, 2011.

Nix, Steve. “The Catalpa Tree and Its Caterpillars.” About.com – Forestry.

Tree Musketeers. “Tree Identification Guide.” This excellent resource was sent to me by a member of the Green Teens Club.

More Catalpa Tree photos:

All photos by author

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