The catalpa tree (Catalpa spp. is loved and known for its height, huge heart-shaped leaves that can be up to 12″ long and 8″ wide, twisted, spreading branches, clusters of creamy white, fragrant flowers, and long, dark brown seed pods. People sometimes call it a “weed tree” because it grows quickly and pops up in strange places. However, many people love having these big, beautiful shade trees on their properties. These names became popular in the Northeast US around the turn of the century. Streets and cul-de-sacs are often called “Catalpa Terrace” or “Catalpa Circle.” “.
It is native to North America, the Caribbean, and East Asia, and is also called the southern catalpa, the hardy catalpa, the western catalpa, the northern catalpa, the catawba, the cigar tree, and the caterpillar tree. Its been cultivated throughout the US since the early 1800s. Bees, butterflies, and hummingbirds like the flowers and use them to spread pollen. This tree is also the only home for the catalpa sphinx moth. With its thick branches and big leaves, the catalpa is a great place for many kinds of birds and animals to hide and rest. The trees hardiness once made it an important source of lumber, particularly for railroad ties and fence posts. It can be found in many big parks because it is hardy and has a beautiful shape in the landscape. However, as an urban tree, the leaf litter can be a problem near sidewalks and cars.
Growing a catalpa tree from seed is easier than you think! With just a little patience and TLC those tiny catalpa seeds can transform into a towering graceful shade tree with huge, heart-shaped leaves and showy spring flowers.
As a self-proclaimed gardening enthusiast, I was determined to try growing catalpa trees after spotting their whimsical seed pods hanging like bean pods outside my local nursery. Catalpa trees aren’t usually grown from seeds by the pros – they’re propagated from cuttings to keep their desirable traits. But for us amateur gardeners, growing from seed is a fun experiment that connects us to the natural rhythms of trees.
In this article I’ll walk you through how I grew my beloved catalpa tree (nicknamed “Beanstalk”) from seed to a 12 foot tall sapling. Read on for tips on when to harvest seeds, how to store them, how to plant them, and how to care for your baby catalpa tree.
Step 1: Identify and Harvest Catalpa Seed Pods
Catalpa trees produce slender, bean-like seed pods in summer and fall. The pods ripen from green to brown, eventually splitting open to release papery seeds contained inside.
To find fresh seed pods, look for established catalpa trees in your neighborhood in mid to late summer. I spotted my first catalpa near a park bench, with giant heart-shaped leaves and huge pods dangling overhead.
Catalpa pods should be harvested when they are mature and brown, but before they split open. I would inspect the pods frequently and harvest them as soon as they turned an even brown color. I used gardening gloves and pruning shears to carefully snip the stems and collect the pods into paper bags.
Each pod contains hundreds of catalpa seeds! One mature catalpa tree can produce thousands of seeds, so you only need a few seed pods to get started.
Step 2: Extract and Store Catalpa Seeds
Once home, I left the seed pods in a dry, well-ventilated area for a couple weeks. This allowed the pods time to fully ripen and split open, making it easy to extract the seeds inside.
Catalpa seeds are flat and papery, with a wing-like border. After removing the seeds, I let them dry for 2-3 more days on a paper towel before transferring them to ziplock bags for storage.
Proper seed storage is crucial for good germination rates! Catalpa seeds require cold, moist stratification to break dormancy. I stored my seeds in the refrigerator in damp (not soggy) perlite. Stored this way, catalpa seeds can remain viable for over a year.
Step 3: Plant Catalpa Seeds in Spring
After overwintering my seeds in the fridge, I was ready to plant them in early spring, right after the last frost. I filled small pots with seed starting mix and sprinkled the seeds lightly on the soil surface. Catalpa seeds need light to germinate, so they should not be covered with soil.
I kept the planted seeds in a sunny spot indoors at around 70°F. Seed starting heat mats can provide bottom heat if needed. To retain moisture, I covered the pots with plastic wrap until the seeds began to sprout.
Step 4: Care for Catalpa Seedlings
Within 3-4 weeks, tiny catalpa seedlings emerged! When the seedlings developed their second set of leaves, I transplanted them into individual pots. Catalpa trees have a taproot, so choose deeper pots if possible.
Catalpa seedlings need consistently moist (but not soaked) soil, frequent misting of leaves, and protection from harsh sunlight. Slow-release fertilizer can be added when re-potting to provide nutrients. Proper lighting is important, so a grow light may be needed indoors.
By midsummer, my catalpa seedlings were over 12 inches tall with large, recognizable leaves. It was time to transplant them into the garden! I amended the soil with compost and planted the saplings in a sunny, sheltered spot.
Step 5: Enjoy Watching Your Catalpa Tree Grow
A decade later, my catalpa tree is over 40 feet tall and its huge leaves provide ample afternoon shade. Each spring, dazzling clusters of frilly white flowers cover the branches, attracting hummingbirds and butterflies.
Temperature and Humidity
As catalpas are native to warm, temperate areas, their growing zone range is limited to 4 to 8 (depending on species). However, they are a hardy deciduous tree that can handle cold winters and hot summers most of the time. Its not overly bothered by high humidity or dryness.
Light
The catalpa does best with at least four hours of direct sunlight per day. It prefers full sun to really thrive.
How to grow a Catalpa Tree from seeds – Part 1
FAQ
How long does it take to grow a Catalpa tree from seed?
Do catalpa seeds need cold stratification?
How do you propagate a Catalpa tree?
How do you grow a catalpa tree?
Store them in in a cool, dry place until summer until the seeds are sown. Well-draining, moist soil is essential for sowing catalpa tree seeds. Sow the seeds in well-draining potting soil in 3-inch pots, or in well-drained soil in a cold frame in a partial-shade site. All pots for catalpa seedlings must have drainage holes.
How do you harvest Catalpa seeds?
You can harvest the seeds by cutting the pods. Just make sure you leave at least two seeds on each pod. You may want to wait until spring before harvesting the seeds because it will take a while for the pods to mature. You can buy catalpa seeds at any garden center or nursery.
When should I plant a catalpa tree?
Plant young catalpa trees after the final average frost date for your area. Catalpa trees produce seed pods that burst open in the fall to reveal catalpa seeds. Harvesting the seeds to plant in the spring is a simple task, but one that requires patience.
How long does it take for Catalpa seeds to germinate?
Fill a 2-inch planting container with good quality commercial potting soil. Any container will do as long as the bottom has good drainage. Plant a catalpa seed about 1/4 inch deep, and water it lightly. Put the container in a cool place that gets low sunlight, and keep the soil moist until the seed germinates. This should take about 15 to 21 days.