En EspaŅol

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
Can't find the answer in our existing FAQs, submit a question to Mr. Smarty Plants.
Need help with plant identification, visit the plant identification page.
 
rate this answer
Not Yet Rated

Thursday - June 20, 2013

From: Buckley, WA
Region: Northwest
Topic: Pests, Shrubs
Title: Spots on calycanthus petals from Buckley WA
Answered by: Barbara Medford

QUESTION:

Petals on calycanthus develop black spots the turn into holes. Problem appears shortly after buds open. Occurs every year. Foliage is healthy. Plant growing well and doubles or triples size every year. Has been in present location about four years.

ANSWER:

There are two members of the Calycanthus genus native to North America. This USDA Plant Profile of Calycanthus floridus (Eastern sweetshrub) shows it growing nowhere in western North America. According to our webpage on Calycanthus occidentalis (Western sweetshrub) it is endemic to California. The USDA Plant Profile shows it growing only in Klickitat County of Washington, a couple counties away from you in Pierce Co., but we assume the climate, rainfall and soils are nearly enough alike that it will do all right in your garden.

From our webpage, here are the growing conditions for Calycanthus occidentalis (Western sweetshrub):

"Growing Conditions

Light Requirement: Sun , Part Shade
Soil Moisture: Moist
Soil Description: Moist soils.
Conditions Comments: Calycanthus occidentalis will develop leaf burn if planting site is too dry."

Please note the comment on leaf burn, if the site is too dry, as well as the need for sun (6 hours or more of sun a day) or part shade (2 to 6 hours of sun), but that is referring to leaves, and we assume you are finding the spots on the petals of the flowers. So, we will look further and see if we can find an explanation of the spots on blossoms.

Here is more information and pictures from Las Pilitas Nursery in California. From that, we learned that pollination is by members of the Nitidulidae family of beetles. Further research said that these are sap sucking beetles, and we could not find any indication that they did damage to flowers they were pollinating.

All the references we searched said that the plant was relatively pest and disease free. Since, as you say, the plants are healthy, we would not be too worried about it. We are native plant gardeners, not entomologists, but if you are concerned, you might contact the Washington State University Extension Office for Pierce County to see if other similar occurrences have been reported in your area.

 

From the Image Gallery


Western sweetshrub
Calycanthus occidentalis

More Pests Questions

Getting rid of Aphids on Asclepias plants in Brea, CA.
July 23, 2012 - I grow asclepsias or MILKWEED for the benefit of Monarchs. At times I have aphids consuming the leaves. How can I destroy the aphids without harming the Monarch eggs? Thank you very much.
view the full question and answer

Tulip tree with white spots on leaves in Mississippi
July 31, 2008 - I have a tulip tree in my yard that blooms in the spring that is about 10-15 years old. However just this past week or so we have noticed that there is lots of white spots on the leaves and the branc...
view the full question and answer

Is oak leucanium an invasive species in Texas from Laredo TX
April 02, 2013 - Is Parthenolecanium quercifex considered an invasive species in Texas? Does this insect attach itself to redbuds? I spotted and removed from my small 5ft Texas Redbud last year. It seems that it has ...
view the full question and answer

Mealy bugs on plants in Washington, DC
July 07, 2011 - Dear Mr. Smarty Plants, There is this white stuff, looking like snow flakes, that is attacking my office plants. I use gasduster to blow it off of them, but that does not stop it from reappearing. Wh...
view the full question and answer

Plants to repel mosquitoes from Leander TX
May 19, 2013 - What are the best plant for repelling mosquitoes in the Leander area? The land here is hilly and rocky.
view the full question and answer

Smarty Plants's Facebook profile Support the Wildflower Center by Donating Online or Becoming a Member today.

Mr. Smarty Plants wants you to be his Facebook friend. Click the Facebook icon to add yourself to Mr. Smarty Plants list of friends.
E-NEWSLETTER | BECOME A MEMBER | DONATE NOW | MEDIA | SITEMAP | STAFF
© 2015 Lady Bird Johnson Wildflower Center