Garden Detective

Philodendron’s ‘flower’ has her mystified

Reader Leslie Carroll-Tipton wants to know how to promote blooms on her split-leaf philodendron, Philodendron bipinnatifidum, which is native to rain forests in Paraguay and Brazil.
Reader Leslie Carroll-Tipton wants to know how to promote blooms on her split-leaf philodendron, Philodendron bipinnatifidum, which is native to rain forests in Paraguay and Brazil.

Q: I planted this split-leaf philodendron almost 10 years ago along with two others in my backyard, but I have never noticed any flowers in the past. This plant appears to have six very large flower buds. This one started opening yesterday, but it had closed back up this morning. What am I dealing with, and how can I encourage their growth?

Leslie Carroll-Tipton, Sacramento

A: Congratulations! Your plant is finally mature (and happy) enough to sprout “flowers.” Your other philodendrons likely will follow suit – if not this year, then soon.

According to UC master gardeners, your lovely large-leaved plant is Philodendron bipinnatifidum. The common name is split-leaf or tree philodendron.

This “tree,” which can grow 15 feet high and just as wide, is native to the rain forests of Paraguay and southeastern Brazil.

The “flower” on your plant is actually a hoodlike spathe that can reach more than a foot long. Inside the spathe is an upright spadix covered with hundreds of tiny petal-less flowers. The “flower” will stay on the plant for weeks before finally turning brown and withering back, when it can be removed. All the plant needs to keep its blooms intact is regular irrigation.

This tropical plant is very popular in California, where it grows well outdoors. Take care in placing a tree philodendron, lest it encroach on walkways or grow too close to buildings; a small specimen will get very big. The leaves often reach 3 feet long.

The tree philodendron doesn’t like full sun and grows well in dappled or partial shade. It also is not drought-tolerant and grows best in fairly moist, well-drained, fertile soil. It needs at least twice-a-week irrigation in hot weather.

Give it some additional water on windy days. In the winter, keep the soil just barely moist. Most winter injury is from drying out, not cold temperatures.

Tree philodendron has thinner leaves than most species in the genus and therefore needs a little more humid atmosphere such as occasional misting. Mulches help prevent water loss during hot, windy or sunny weather.

It requires little care except the occasional removal of lower leaves that become discolored.

This is one of the hardiest of all philodendrons, and can grow well in USDA Zones 9 through 11.

Frost may kill the leaves of tree philodendron or even kill the whole plant to the ground. But if the cold is not too severe and if the plant is well established, it will come back as the weather warms.

Wait until all danger of frost is past before removing damaged leaves, no matter how awful they may look.

Prune for size control and pedestrian safety, to remove dead or diseased plant parts or to shape or train plants.

The tree philodendron can be cut as hard as needed, even back to main trunks. New growth sprouts near the cut ends. Prune in the late winter or spring, depending on when the plants flower.

But heed this warning: Philodendrons are poisonous if eaten and the sap may irritate sensitive skin. Wear gloves when pruning or removing old growth.

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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