I photographed this unusual tree in a park in Jacksonville, Florida. The orange things are ripe fruit, and the green ones are .....green fruit. What is this tree, and why is considered to be an undesirable, invasive species?
This is a Paper Mulberry Tree. Its leaves look very much like our normal mulberry, but the fruits are MUCH different. It is native to eastern Asia, but here in the US, it is a very invasive species. First, they spread very rapidly, and if you cut one down, many more spring up from its roots. Its roots are very shallow, so it blows over easily in strong winds, but the roots are very powerful when it comes to breaking into small cracks in rocks, concrete walls, and underground plumbing. If you cut the tree, it exudes a very sticky, latex sap. It also produces huge amounts of pollen, which can cause severe allergy problems. Its fibrous wood is very difficult to cut, and tends to dull saws quickly. All in all, it a pretty tree that can cause big problems. The fruit is edible, but is too delicate to be commercially used. Just holding one in my hand caused it to come apart, and make a mess.