Wednesday, September 28, 2011

Native Plants That Develop Burs

I have been spending a lot of extra time lately pulling burs from my dog's coat during and after our walks. There are many native perennials that have maturing seeds right now, several of which have some sort of hooked hairs or prickles that are ideal for attaching to animals as they pass by. Animal dispersed seed is an ingenious way to distribute seed a good distance away from the parent plant.

White Avens ~ Geum canadense


White Avens is a native perennial of dry, upland sites in woodlands. The white five parted flower opens in mid June on a flower stalk that is 12-18" in height.

The round cluster of seeds that develop have hooked ends and fine hairs that catch on animals passing by.
Downy Agrimony ~ Agrimonia pubescens


This is also a native perennial of dry sites in partial shade. The five parted yellow flowers open from the bottom upwards on the flower stalk, starting in mid July.

The cluster of seeds is enclosed in a bell shaped capsule with hooked hairs protruding from the top.

Pointed Leaved Tick Trefoil ~ Desmodium glutinosum


I featured this native earlier this year as the Plant of the Week.

Found in dry to medium woodlands, its flowers open in late June. Tolerant of quite a bit of shade, it is often found growing right up to the trunks of large trees.
The light pink (pea-like) five parted flowers are very attractive, set high on the flower stalk above the low foliage.

The flat pods are covered with tiny hooked hairs. As they mature to a medium to dark brown color they will readily stick to all types of clothing and animals.

American Lopseed ~ Phryma leptostachya


American Lopseed is also a woodland perennial with opposite arranged leaves. The light pink to white 4 parted flowers open in early July. It prefers medium to moist lower lying locations.

In the fall, the foliage turns golden yellow. The seeds hang downwards along the flower stalk and have hooked tips.

This photo is of some immature seeds (not yet brown) showing the hooked tips.

Enchanter's Nightshade ~ Circaea lutetiana


Another woodland perennial with opposite arranged leaves. Tiny, white, 2 parted flowers emerge in mid June. This is a common plant of disturbed woodlands, spreading by shallow fleshy rhizomes.

The round 2 capsuled seed is covered with small hooked hairs.

Sweet Cicely ~ Osmorhiza claytonii, Osmorhiza longistylis


Sweet Cicely is an early flowering perennial, starting around the beginning of May. It is a tall plant, reaching heights of up to 3 feet in good soils. It prefers medium to moist locations but can also be found in drier upland woodland sites.

The 5 parted white flowers are arranged in an umbel.
Seeds form in pairs and split apart into two seeds. The long black seeds are covered with tiny white hairs. These seeds are very good at embedding themselves into the undercoat of my dog, often sight unseen until I run my hand over his coat.


These are just a few of the many native perennials that produce burs or seeds with hooked hairs.