Contact Us Host an Event Volunteer Join

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.

Help us grow by giving to the Plant Database Fund or by becoming a member

Did you know you can access the Native Plant Information Network with your web-enabled smartphone?

Share

Ask Mr. Smarty Plants

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

Search Smarty Plants
See a list of all Smarty Plants questions

Please forgive us, but Mr. Smarty Plants has been overwhelmed by a flood of mail and must take a break for awhile to catch up. We hope to be accepting new questions again soon. Thank you!

Need help with plant identification, visit the plant identification page.

 
rate this answer
Not Yet Rated

Tuesday - April 12, 2005

From: Pittsburgh, PA
Region: Mid-Atlantic
Topic: Plant Identification
Title: Differentiating between Spiraea betulifolia and Spiraea japonica
Answered by: Joe Marcus

QUESTION:

How can I tell the difference between Spiraea betulifolia var. corymbosa (an imperiled species) and Spiraea japonica (an invasive species) in the wild? They both seem to be the same size, color, habit, etc.

ANSWER:

There are a couple ways to distinguish Spiraea betulifolia var. corymbosa from Spiraea japonica. Unfortunately, there are also some pitfalls in these distinctions! In general, our native spirea is white-flowering (occasionally lightly blushed pink), while S. japonica is typically pink to rose-red flowered. The exceptions are uncommon, but can make positive identification difficult. The leaves of S. betulifolia var. corymbosa are broadly ovate to oblong or obovate, between 4 and 7 cm long and usually less than twice as long as wide. If you are not familiar with botanical terminology think, "arrowhead shaped". Spiraea japonica leaves are lanceolate or lance-ovate, between 8 and 15 cm long and 2.5 to 5 cm wide, or typically more than twice as long as wide. Think, "spearpoint or lancehead shaped". Further, the toothed edge of Spiraea betulifolia var. corymbosa usually extends only from the leaf tip to 1/2 to 2/3 of the length of the leaf toward the base, while the toothed edge of S. japonica leaves typically extend nearly to their base. Spiraea japonica escapes from cultivation and can often be found growing in the wild. To further complicate matters, the many cultivars of S. japonica can confuse identification.
 

More Plant Identification Questions

Books for plant identification of native California species
March 14, 2008 - When I was going to college, many years ago, there was a field book for plant identification for California native species. I am trying to find that book again or at least a good pocket book on plant...
view the full question and answer

Seeds of Castilleja purpurea
April 12, 2012 - The seed photo for Castilleja purpurea is incorrect; seeds are black and poppyseed size.
view the full question and answer

Plant Identification
March 11, 2009 - Hello. I don't know if this is a North American native plant, but here's my question: I have a soft, low groundcover that looks like a miniature version of Foxtail Fern. Lowe's folks suggested it m...
view the full question and answer

Plant identification
July 29, 2008 - I have found what resembles a gooseberry growing from what appears to be a grapevine trellising on a fence beside a lake in East Texas. The stems are smooth and slender, nad as I stated before vine up...
view the full question and answer

Plant identification
August 03, 2008 - 6 2 ft. spikes appeared in an infertile part of my garden. They have a huge quantity of very tiny ochid-like flowers, mostly white with pink tinge. I took it to the master gardeners here and no one co...
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.