Submitting Woody Plants

Trees and shrubs problems?

Observe symptoms and patterns, document what you see with pictures while inspecting the plant.  Visit our Digital Photography page for some guidelines.

Follow our guidelines for examining unhealthy trees at the resource Identifying Tree Problems (free pdf)

Before submitting a sample, consider taking good digital pictures of the symptoms. What is the pattern? 

Download and fill out our form as completely as possible. 

Leaf spots 

  • Collect several  (3-5) twigs with leaves attached, pack in clean, absorbent material (such as paper towels, newspapers) to absorb all leaks, in a plastic bag. Do not add moisture.

Canker problems

  • When submitting cankers, include portions of the branches at the border between discolored and healthy bark (see photo).


Woody sample example. Left, provide plenty of plant material. Right observe cankers

Root rot problems (shrubs)

For some diseases, even though the symptoms are observed in the leaves, the pathogen is located in the root and crown.

Contact us with photos at pidc@iastate.edu, and we can tell you if we recommend sending a sample of the plant root ball and crown.

For root rots and crown root confirmation, digging the root ball (see photo below) and send it along with some stems. The root ball and crown is the best tissue for us to recover (isolate) the pathogen.

crown and root sample example
Shrub crown and root sample example

Packing and shipping

  • Do not add paper towels or water along with the sample. Excess moisture can cause rapid deterioration of the sample and the proliferation of secondary organisms.
  • Pack your wrapped sample tightly in a box. Ship the package early in the week via overnight delivery. Walk-ins are welcome!

Suspect a wilt problem?: Plant losing leaves from the top of the canopy or one side of the crown, leaves turn yellow to brown and drop (earlier than fall season)

Go to Vascular wilts testing page