Someone who is looking for a flowering shade tree may typically seek out various qualities. Typically the goal is to get a tree that is fast-growing, with abundant flowers, and a large shade canopy that is resistant to insects and disease. The Royal Paulownia, also known as the Princess Tree or Foxglove Tree, fits all those qualities. However, those assets can turn out to be problems.
Really Big, Really Fast
The Royal Paulownia is a fast-growing shade tree. However, you may get more than you bargained for. Namely, you may end up with a giant tree. Known to grow 15 feet in a year with a top (or canopy) to match, you may soon have a 40- or 50-foot tree with a canopy of similar size creating a dense shade where not much else will grow.
Lots of Seeds
Once mature, your Royal Paulownia tree will produce an abundant amount of seedpods or capsules. Inside each pod are almost 2,000 seeds that germinate rapidly wherever they fall. You must weed out young Paulownia trees; or, left on their own, they can soon become invasive. In some states they are on the Invasive Plant list (check with your State's Department of Natural Resources or your county extension office for your area).
What a Mess
When the Paulownia tree is several years old, it will blossom profusely with very large, fragrant flowers followed by an abundance of leaves. A 40-foot tree with a canopy 40 feet across will have a lot of flowers and leaves. First, all those flowers will fall to the ground. Later all those leaves will be shed, mixed in with twigs, littering the ground beneath. It is an accumulation that can hardly be ignored.
Big and Broken
One of the desirable qualities of the Paulownia tree is its rapid growth. That same quality, however, is a drawback. The rapid growth does not give the tree time to create a thick dense cell structure to support its massive height and spread. To this rapid growth spurt, add the weight of an impressive flowering display, and the wind easily snaps off treetops or branches when the tree is in full bloom.
The Root of the Problem
The crown or canopy of your Paulownia tree is matched by its massive root system. The roots spread out underground and along the surface as far out as the canopy spreads. These aggressive roots can become a problem for underground pipes (septic systems), crack and lift sidewalk sections, or make mowing the lawn a bumpy prospect.