These vertical shoots are called water sprouts. They are fast growing branches that can often overtake the leader. Usually they appear in a tree that has been over pruned or is under stress. It is a good idea to find out the probable cause and remedy the situation. You should remove water sprouts before they get too big. They tend to have weak attachments. If you let them develop into big branches they have good chances of breaking off.
Water sprouts also suck up too much energy. The energy they use detracts from the tree’s regular growth. Unfortunately sometimes if you remove them they just grow back. If this happens, the next time you prune just take out the big ones and leave a few of the small ones.
In this case, I think that this plum tree is under some stress; the root system remove is poor. How could I tell? A sure sign is to lightly shake the tree trunk. Watch the ground. If the ground moves, there is poor root structure. The ground moved somewhat when I shook the tree. However, I don’t think the tree is in too much danger of falling over. Whoever planted the this plum tree may not have sufficiently broken up the root ball. Or, it had spent so much time growing in a small pot that it will take much longer to form a healthy root system
Trees are smart. When they get knocked around by the wind they react by growing support roots. If they are tied up to a stake then they learn to rely on the stake. If the tree can’t support itself in a windstorm then it should come out before it gets too big.
I removed the biggest water sprouts and the stakes. We’ll see how this tree fares a year from now.
This plum tree needs some young tree training. It was planted by Friends of the Urban Forest several years ago. They usually take care of trees for three years after planting. This includes stake and tie adjustments and some pruning. After three years it is the owner’s responsibility to maintain the tree.
The owner of this tree got a notice from the city advising him to have an arborist help with the upkeep. There was not much work to be done, but the work was very important. Street trees are exposed to the elements without a natural environment. They can get very thick and bushy, creating a wind sail. They also can grow too low over the street or sidewalk and thus more prone to break. If you get an arborist to train your tree when young you will end up with a longer living, more beautiful, healthy tree. It is also better for the tree to train the structure while still young rather than waiting until you have to make bigger cuts or waiting until there is damage or the tree falls over.
I also took the stakes away, since they were no longer necessary.
Here is a beautiful tree on Piedmont St, near Asbury, in San Francisco. This American Sweetgum is technically a deciduous tree, but here in our Mediterranean climate they don’t normally lose all of their leaves at once. They look a lot like Maple trees. Some of them have better fall color than others.
California coast Redwoods need moist, temperate air, humos rich soil. They naturally grow in valleys. They don’t like wind. Yet, people love them and want to plant them in windy San Francisco and in the dry central valley. So they look okay for ten, twenty years. But they they turn brown. And they call me. And I have to tell them it probably shouldn’t have been planted in the first place.
Sycamores are riparian trees, but require a drier climate. They hate wind. Yet we continue to plant them all over San Francisco. Why? Who knows? They look terrible in Civic Center; thin, barely any foliage, leaning away from the wind. They keep planting them on Valencia. It’s too bad.
Jacarandas, from Brazil, need lots and lots of sun. They look great in Mexico City. Flying in to the city in March, the ground is blanketed in purple. In San Francisco they generally look sick. Some years are better than others. Sometimes they bloom well, sometimes not. This is not a tree I would plant here.
So before you choose a tree for your desired location, consider your soil type, the wind, water availability, and sun exposure. Sometimes the recipe for a successful planting can come down to being on the sunny side of the street or away from a wind tunnel.