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Q. Who is Mr. Smarty Plants?

A: There are those who suspect Wildflower Center volunteers are the culpable and capable culprits. Yet, others think staff members play some, albeit small, role. You can torture us with your plant questions, but we will never reveal the Green Guru's secret identity.

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Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.

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Sunday - April 10, 2016

From: Boerne, TX
Region: Southwest
Topic: Problem Plants, Shade Tolerant, Trees
Title: Why doesn't my Rusty blackhead bloom?
Answered by: Guy Thompson

QUESTION:

I have planted Rusty blackhaws the past several years..some bloomed the first year and every year since....and others 3 years old have not bloomed yet... Do all Rusty blackhaws bloom eventually or are there male plants that do not bloom..??

ANSWER:

One of our previous answers addresses this question. 

"According to the chart in Tree Sex: Gender & Reproductive Strategies from Warnell School of Forestry and Natural Resources, The University of Georgia, Viburnum rufidulum (Rusty blackhaw viburnum) is neither monoecious (male and female reproductive structures on the same plant but in separate flowers) or dioecious (male and female reproductive structures on separate plants).  It is cosexual or hermaphroditic (male and female structures together in the same flower)."

Therefore, all plants have the capability of blooming.  I have read that while Rusty blackhaw thrives as a small understory tree it blooms most prolifically in full sun.  It makes me wonder if your trees that have not yet bloomed are in a more heavily shaded location than your blooming trees.  That is the only reason I can think of unless the plants are simply not yet old enough to bloom.

 

 

 

 

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