The empress tree (Paulownia tomentosa) is beautiful and fragrant, and it grows unbelievably fast. Its flowers are a gemlike shade of purple, and their shape unusual and unique, while its heart-shaped foliage can grow to an astounding width of 30 inches. You will think it is stunning—but think about planting something else. In just a few short years, it could become a problem in your yard.
|Botanical Name||Paulownia tomentosa|
|Common Name||Empress Tree, Royal Paulownia, Foxglove Tree|
|Plant Type||Deciduous Tree|
|Mature Size||30 to 40 ft. tall, 30 to 40 ft. wide|
|Sun Exposure||Full sun|
|Hardiness Zones||5-8, USA|
Empress Tree Care
Unfortunately, the empress tree is appealing to look at, but it is not good for your landscape, property, environment, or local ecosystems.
At first, the tree smells heavenly, like vanilla, and the tree blooms with thousands of flowers in the form of foxgloves every late April and early May. But this seeming benefit of the tree is actually its greatest drawback: the fruit on each of those flowers hold 2,000 seeds, with a single tree capable of casting 2,000,000 seeds a year. Additionally, the empress tree can grow 20 feet in a single year. The potential for the tree to become invasive is tremendous, and the potential for it to take over a landscape if you fail to remove a stray seedling is just as high.
Even if you are a fantastic seedling hunter and can prune your tree diligently, this tree can still quickly become an unwelcome guest. The roots are thick, widespread, and destructive with the potential to cause root damage. Determined to spread, the tree eventually sends up voracious suckers from its root system as fast-growing as the main tree.
What this all means is that you have a tree that has an unquenchable thirst and will sap all the water from nearby plants and trees in the area. The roots will make digging and planting other plants difficult.
The empress tree is an invasive species that aggressively spreads seeds and sends up suckers. Check with your local extension office to see if it is classified as invasive or illegal to plant in your state, county, or municipality.
In order to achieve the full amount of blooms you will want to give your empress tree full sun, at least 6 hours of direct sun a day. If you are not worried about getting profuse flowering it will tolerate partial shade without any negative affects.
Ideally, its preferred soil is moist and rich, but it will grow in almost any condition. It has been known to grow in sidewalk cracks, uncleaned rain gutters, sandboxes, and firepit ash, so there's no real need to fuss about the soil conditions too much with the empress tree.
The tree is pretty darn near indestructible once established, but it does require some care, including ample watering. After planting the tree, be sure to mulch two to three inches deep out to the drip line without touching the trunk to help retain moisture. You will want to water it weekly at a rate of two to three gallons of water per inch of its trunk diameter. Carry on with this regimen during the first season until autumn. Further supplemental watering shouldn’t be needed going forward.
Temperature and Humidity
Empress trees are hardy. Very hardy. They can withstand temperatures from -10 degrees Fahrenheit high and temperatures up to 120 degrees Fahrenheit, but these temperatures are deceiving. The tree is actually a lot less tolerant than these numbers express. The empress tree’s roots are hardier than its stems. Flowers and leaves will die at 0 degrees Fahrenheit, and the entire trunk will die at -10 degrees Fahrenheit if the cold lasts more than a short time.
There is no need to fertilize the empress tree. It will grow readily in most conditions and does not need much of a boost to get it to thrive. It is known as a pioneer species and can grow in conditions that other species find inhospitable.
What Is a Pioneer Species?
A pioneer species is the first species to colonize an ecosystem that is previously damaged or disrupted.
Taking on this chore can be a matter of preventing property damage and trying to manage the insanely fast growth. You will want to clear branches that may be susceptible to snow or wind damage or present hazards.
But be careful when pruning: empress tree wood is notoriously weak, and making poor cuts and using improper pruning technique can lead to further weakening the wood.
When trying to control the empress tree’s aggressive growth, numerous techniques are employed depending on the desired result. To curb the growth and keep the tree a manageable size, you will want to cut your tree down to about five feet every autumn. Doing this will allow the tree to grow back and bloom every spring.
If rather than having blooms you'd prefer to have an interesting shrub with fascinating foliage 36 inches in width, cut just above the ground level. Doing this will not let flowers or fruit appear but will create some spectacular foliage.