How To Grow And Care For An Empress Tree

The empress tree (Paulownia tomentosa), sometimes also known as the princess tree or Royal Paulownia, is adorned with lovely purple, vanilla-scented flowers and big, beautiful, velvety leaves, and it grows very quickly. For this reason, it is a popular tree to plant for quick shade. The empress tree is actually one of the fastest-growing trees in the world and has been known to grow up to 20 feet within its first year, so you'll be able to enjoy its beauty sooner than you might expect. As a bonus, its wood is very valuable. In fact, it's so valuable that people sometimes steal young empress trees in the dead of night. There are downsides to growing a tree this rampant in certain climates, so here are all the facts about this beautiful tree and where and how to grow it.

The Empress Tree's Royal Roots

Named for Princess Anna Pavlovna, daughter of Czar Paul I, the empress tree is native to central and western China, where its wood has been used for more than a thousand years to make furniture, musical instruments, wood carvings, pots, bowls, and spoons. The Japanese also prize it highly as the perfect wood for making sandals (click to see some nice ones). Wood from empress trees is blond in color, very easy to work with, nearly as light as balsa but twice as strong, has a silky feel, and resists insects and decay. Nice empress trees with straight trunks can fetch thousands of dollars, which is why they're subject to thievery. Many people have gone to bed with thriving empress trees on their property, only to discover nothing more than stumps in the morning.

Plant Attributes
Common Name	Empress tree, princess tree, royal empress tree, royal Paulownia
Botanical Name	Paulownia tomentosa
Family	Paulowniaceae
Plant Type	Deciduous tree
Mature Size	50 ft. tall, 30 ft. wide
Sun Exposure	Full, partial
Soil Type	Moist, well-drained, sandy loam
Soil pH	Mildly acidic to mildly alkaline (6.0-7.5)
Bloom Time	Spring
Flower Color	Light purple
Hardiness Zones	5-9 (USDA)
Native Area	Asia

How To Care For Empress Trees

Empress trees are incredibly easy to grow. You will want to plant them in fertile, well-drained soil and give them ample water, especially if you are growing with the intention to sell their valuable wood. The soil should be more acidic than alkaline and preferably moist, sandy loam. Typically, you can expect thousands of flowers to bloom on an empress tree in late April or early May, but if you are not opposed to having fewer flowers, more shade will not harm the tree. Conscientious pruning will be key to curbing your empress tree's rampant growth and keeping it to a manageable size. We recommend cutting this fast-growing shade tree to around 5 feet tall when autumn comes.

Where Not To Plant Empress Tree

Even though they are very valuable and could potentially make you a fortune, I must let you know the unfortunate truth about empress trees. Much like catalpas, mulberry trees, and the tree-of-heaven (Ailanthus altissima), the empress tree belongs to a class of trees that some consider to be less-than-ideal. Not only does it seed all over creation, producing as many as two million seedlings per year, but it will also sometimes grow in absolutely terrible soil where few other trees will. You'll often see it growing on old mining sites, next to railroad tracks, out of cracks in the pavement, or on rocky cliffs. The trees pictured at the start of this article are growing on buried busted-up concrete rubble. If you cut an empress tree to the ground in spring, it is extremely likely that it will grow 10 feet within the next year and sprout gigantic leaves.

Empress trees grow so rampantly that they are classified as a noxious weed in Connecticut, where sales of this species are actually banned. They are considered invasive in the Southeast, and state governments from Tennessee to Florida recommend against planting them. Planting an empress tree too close to a garden or other trees will often result in the empress hoarding nutrients and water from the nearby plants. If planted too close to a building, the roots have a strong potential to damage the foundation. Therefore, the empress tree is not recommended for landscaping. If you decide to add one to your property, it is imperative that you ensure that it has ample room to grow and is far enough away from any buildings and other plant life. It's also recommended that you do as much as possible to remove any stray seedlings that fall, or else you may have multiple empress trees sprouting in your yard. If that happens, be sure to uproot them long before they've had time to mature. You do not want a yard full of these giants, despite their beauty.

Light

Empress trees do best in full sun. Partial light shade is okay for this tree but it prefers to be in full sun, for at least six hours a day, in order for most of its flower buds to fully bloom—particularly because the flower buds are often damaged by early spring frosts.

Soil

Empress trees are very tolerant of most soil types, even growing in rocky, shallow, infertile soil in disturbed areas of forests. But the trees prefer deep, moist, sandy loam. Heavy clay is not recommended. This tree cannot thrive in very acidic soils with a pH under 5.0, but will grow in soils that are mildly acidic, neutral, or mildly alkaline.

Water

This tree will grow best in a moist, but well-drained site. Water during dry spells while the tree is getting established. Empress trees can handle dryer soil once they mature.

Temperature And Humidity

Empress tree is hardy in most of the South, and is found growing from New York down to Florida and west to Texas. The tree flowers well in climates with long, hot summers. Lack of cold-hardiness is one limitation if you are growing this tree for its flowers, though. Flower buds are usually killed north of the Upper South (Zone 6). Avoid planting in a site exposed to cold winter winds.

Fertilizer

The empress tree doesn't require fertilizer, but an annual application of nitrogen will help support its rapid growth. Use a balanced slow-release fertilizer like Osmocote.

Pruning

Because it grows so fast, empress trees recover quickly, even when cut to the ground. You can lightly prune this plant in late winter or early spring, removing dead, diseased, and crossing branches. Cutting the tree back to 5 feet tall in winter can be a good middle road for keeping the tree at a manageable size. Pruning the tree back hard (within 3 feet of the ground) will result in bigger leaves, but no flowers for that year. If you do this, remove all but a strong central leader when the tree resprouts. The central leader will form a new trunk and branches.

If you're looking to remove an empress tree, cutting it to the ground won't kill it. You'll have to cut the tree and then paint the stump with a strong glyphosate solution, or cut new sprouts repeatedly until the tree slowly starves and dies.

Propagating Empress Tree

Empress trees seed so easily, you probably won't need to propagate this plant. Experts also say that the tree develops a stronger root system when grown from seed. If you do choose to propagate your tree, root cuttings are the best method to use. Here's how:

1. In winter, dig up a root and cut a section (preferably at the tip) that is 2-4 inches long. Use a sharp garden knife to take the cutting.
2. Place the root cutting on its side in moist sand, sawdust, or peat moss, making sure to note which end of the cutting was growing out from the tree. Store at 40 degrees Fahrenheit.
3. After about three weeks, plant the root cutting in good garden soil. The cutting should be 2 inches under the surface, with the growing tip pointing up.

How To Grow Empress Tree From Seed

You'll have plenty of seed to collect from your tree in fall after it turns brown and dry. Seeds can be sown any time of year, but germinate the fastest in mild weather. You can start the seeds indoors and then transplant in the spring. Here's how:

1. Fill a tray or pot with seed-starting mix and moisten.
2. Sprinkle seeds over top of the mix and water well. If you are sowing outdoors, you may use a plant bed covering designed to allow light and water through.
3. Keep moist. The seeds should germinate in three to five weeks. Remove any covering once seedlings are 2 inches tall.
4. Transplant in the garden in spring.

Common Pests & Plant Diseases

The empress tree doesn't have any serious pest problems, though slugs and other insects may nibble on the leaves. Fungi can infect the tree and cause stem canker, is best treated by an arborist. Planting the tree in a good site and keeping it in good health should deter any fungal infections.

How To Get Empress Tree To Bloom

Poor sun exposure, pruning heavily, or pruning at the wrong time of year can affect your tree's flowering. Increase light exposure if your tree was planted in shade. Limit pruning to right after blooming has finished in spring, or prune lightly.