Interesting example of clonal growth

Lots of bad or undesirable plant species spread vegetatively by underground rhizomes or stolens, and they are some of the worst plants to get rid of. Because their growth processes are occurring underground, it is hard to appreciate just what is going on. Many of the species that are rhizomatous send up new shoots from underground buds, a process called root suckering. Where you see root suckers, you know there are hidden rhizomes.

Common milkweed (Asclepias syriaca) is a good example of a clonal species. Although the butterflies love it, and many people plant it to encourage Monarchs, it is a plant that can easily get out of hand.

The photo here provides an interesting example of how this species grows. The large plant in the background is growing at the edge of a mowed lawn. This lawn was mowed about a week before the photo was taken. Four root suckers are visible, each of which could make a new clone. Since each new shoot can send out its own rhizomes, it would not take long to cover a large area. Although the shoots represent growth in the last week, the rhizomes may have been growing for many weeks under the lawn.

Milkweed shows the "guerrilla" type of clonal growth. Other species that grow in this fashion are aspen and sumac. The other growth type, phalanx growth, shows a tight advancing front. Canada goldenrod is good example of this type of clonal growth.

See this post for a discussion of  guerrilla and phalanx  growth patterns.