I've lived in Sacramento for a few springs now and am still not that familiar with the horticulture. But I do have a burning question.
There were trees in bloom in March that have a very strong odor. They are tall with slenderish trunks and sport beautiful white blossoms.
Unfortunately, the blossoms are the offender. They smell awful. What are these trees?
Lee Kelson, Sacramento
According to UC master gardeners, these trees undoubtedly were flowering pears (Pyrus calleryama). The Bradford variety can be particularly offensive.
We have a 20-year-old fruitless mulberry tree in our front yard. The tree is large and has been allowed to grow at will. We trim out dead limbs every year. Our problem: The tree has destroyed our driveway and walkway. We want to replace the concrete and cut the roots at the grass line. There are three large roots running from the trunk into the driveway and walkway. Can we cut these roots without killing the tree or weakening its support? We don't want it to fall over.
Bob Valentini, Sacramento
According to UC Master Gardener Annie Kempees, the fruitless mulberry (Morus alba) is a fast-growing tree that's popular in the Sacramento Valley. Its root problem may be related to hardpan.
Hardpan severely compacted soil similar to concrete limits deep root growth. Additionally, many mulberries are planted in lawns and don't receive the deep, infrequent waterings they need to encourage deep root growth.
The main roots that you mention are likely buttress roots that keep the tree upright. Cutting them out or back would not be best for this tree.
If you want to replace your concrete driveway and path, Kempees recommends removing the tree and replacing it with a smaller tree with better-behaved roots.
If hardpan is present, dig a hole 5 to 6 feet deep where you want to situate the new tree. (You may need to hire a company with an auger to do this.) After removing the hardpan, fill the hole with quality soil and let it settle before planting a new tree.
Do not plant lawn within 10 feet of the trunk. Water the tree separately from the lawn, making sure to water it deeply once a week. Mulch around the tree, keeping the mulch at least 4 inches from the trunk.
Which tree to plant? Check out the suggestions provided by the Sacramento Tree Foundation at www.sactree.org.
Questions are answered by master gardeners at the UC Cooperative Extension services in Sacramento and Placer counties.
Send questions to Garden Detective, P.O. Box 15779, Sacramento, CA 95852. Send email to firstname.lastname@example.org. Please put "Garden Detective" in the subject field and include your postal address. To contact your UC Extension directly, call:
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