Lady Bird Johnson Wildflower Center - The University of Texas at Austin information

 Ask Mr. Smarty Plants

Parasitic paintbrush


Topic: Native Plants, Wildflowers
Author: Joe Marcus and Damon Waitt
Date: Sunday - March 29, 2009
From: Boston, MA

QUESTION: Many years ago I tried to grow some paintbrush seedlings with some seeds you sent me and found it difficult. Based on pictures in the literature I noticed that paintbrushes do not seem to affect their hosts as drastically as other parasites. Lupines and paintbrushes look well together. From your experience is this correct?

ANSWER: Parasitic plants come in several flavors. Among them, there are obligate parasites, which must parasitize a host plant in order to survive and receives all of its nourishment from the host plant. These plants typically lack chlorophyll. There are facultative parasites which will opportunistically parasitize a host plant given a chance, but can survive and complete its life-cycle without a host. These plants are often called hemiparasites or hemiparasitic plants.

Castilleja indivisa (entireleaf Indian paintbrush) is typical of this group of plants. It can and will parasitize neighboring plants via root connections if living in close proximity, but will also grow and reproduce on its own if no host plant is available. The various species of Indian Paintbrush native to Texas often parasitize plants of the grass family (Poaceae), but they really aren't particularly picky about who their hosts are and will attach themselves to and draw nutrients from any number of plant species. Indian Paintbrushes growing with the assistance of a host plant will almost invariably outgrow a sibling without such benefits. Likewise, a host plant parasitized by a Castilleja will normally suffer quite noticably.

... and, yes, lupines and paintbrushes look terrific together.


Castilleja indivisa


Castilleja indivisa
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