Garden Detective

Should mulberry trees be radically cut back?

This fruitless mulberry tree in Orangevale has been properly pruned – and is quite large. “Pollarding” reduces the branches to knobby stubs, but keeps these large shade trees much smaller.
This fruitless mulberry tree in Orangevale has been properly pruned – and is quite large. “Pollarding” reduces the branches to knobby stubs, but keeps these large shade trees much smaller.

In a discussion with neighbors about the practice of cutting mulberry trees back to nubs in the winter, I maintained that this was an unhealthy practice. They seemed unconvinced. Subsequently, I found that such trimming was called “pollarding,” and is a very old European method of stimulating small tree growth to use as fire wood. I still would never cut a tree back to that extreme; however, I’m curious to know why so many continue to do so, and if it causes problems for the tree.

Paula Herrington, Lodi

Pollarding is indeed a style of pruning, according to UC Cooperative Extension master gardeners. The main limbs of a young tree are drastically cut back to short lengths and each dormant season those branch stubs are again cut back to one or two buds. Over time, branch ends become large and knobby. The tree has a compact, leafy dome during the growing season but is somewhat grotesque during the dormant season.

Why use pollarding? Mulberry trees grow very big, very fast. Left unpruned, a mature mulberry can reach 30 to 50 feet tall and just as wide. Pollarding limits its size to the length of new shoots, in effect dwarfing this big shade tree. In our area, landscapers also use the pollarding method on crape myrtles and willows.

Trees pruned in this method can be expensive to maintain and result in weak growth in the tree canopy. Trees with weaker wood may become hazardous; they drop branches.

Major horticulture associations, including the Sacramento Tree Foundation and The Royal Horticulture Society, recommend selecting a tree that is appropriate for the space in the first place rather than pollarding.

We recently bought a house at the elbow of the street, so we have a really nice-sized backyard, but a very pinched front yard that gets sun almost all day long. We envisioned planting a palm tree in our front yard before we moved into our home. After doing research, we know we do not want a Mexican fan palm because we only have a one-story house so we don’t want this tall skinny tree dwarfing the home. I was told dwarf or pygmy date palms are hard to grow in our cold winters and we’d have to cover it. Windmill palms have fuzzy trunks that we don’t like, and the Pindo palm looks messy and I don’t really like the trunk. What we like is how the Mexican fan palm looks before it begins to shoot up tall and skinny. We like the Pineapple palms, but the top span is so wide, we’d probably infringe on our neighbor’s yard. Is there anything we can get that won’t be too hard to grow, too tall and skinny, or too wide?

Lydia Ajay, Elk Grove

According to UC master gardener Annie Kempees, one palm that may be small enough for what you are looking for and one that will likely survive the winter frosts in the Sacramento Valley is the Brahea armata; its common name is Mexican blue palm. Because this palm is slow growing, it remains appropriately in scale with smaller buildings, but it will eventually develop a fairly massive trunk up to 18 inches in diameter.

Sometimes called blue hester palm, the Mexican blue palm is native to Baja California, loves full sun and can take the cold. It’s hardy down to 15 degrees. At maturity, it will reach about 30 feet tall with a spread of 12 to 25 feet, but it takes a long time to get that big. The trunk is thicker at the base and eventually turns gray. But it’s the blue-green, silvery foliage that makes this palm so stunning and so “blue.”

GARDEN QUESTIONS?

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 h&g@sacbee.com. Please put “Garden Detective” in the subject field and include your postal address. To contact UC Extension directly, call:

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