Few people realize that those summer bedding plants with the round lily pad looking leaves and clusters of red, pink, salmon or white flowers are not actually true geraniums. They are more properly called Pelargoniums.
We have a wild species of cranesbill (Geranium carolinianum) that has been showing itself everywhere since late fall. Several wild geranium species thrive across most of North America from the far north to the Deep South. Plants grow in full sun to partial shade and tolerate drought well. They also perform well on compacted soils.
Another common wild geranium species (Geranium maculatum) is perennial and spreads by creeping rhizomes. Many confuse the two, but the perennial type is taller and lobed leaves are not as divided.
Our Carolina cranesbill is a winter annual. Plants grow about a foot tall. Leaves are attached opposite of each other, and resemble garden geranium foliage except they are deeply dissected. Plants often look silvery because they’re covered with fine minute hairs.
Flowers usually bloom in spring. They are similar in size to the individual flowers on Pelargoniums but clusters are sparser. There are five pink to lavender petals per flower.
The seed capsules split to release seeds. Before opening, the seed capsule resembles the bill of a crane, thus the name “Crane’s bill geranium.” Seeds are a favorite food for the mourning dove.
Leaves are edible but they are high in tannins, so they’re bitter. Rinsing the cooking water helps, like with dandelions or collards, but they aren’t one of my favorite greens.
The most common and important use of this cosmopolitan weed is medicinal. The whole plant is astringent, not surprising since another common name for it is alum root. However, this cranesbill is not related to the true alum plant, although the two have similar medicinal properties. True alums are a type of coral bell in the Saxifrage family.
This true geranium also contains styptic substances, so applying them to wounds will stop bleeding. A medicinal tea from crushed roots can be used as a gargle for sore throats and mouth sores. This bitter concoction is also effective for controlling diarrhea and irritable bowel syndrome when consumed several times a day.
If you don’t want it in your landscaping, controlling this common cool-weather weed isn’t difficult. Removing plants by hand is effective for small areas. They pull easily, especially in well-mulched garden beds.
One reason Carolina geraniums are difficult to totally eradicate once established is that they have hard seed coats. Because of this, seeds may remain dormant for several years and pop up when conditions are right.
Several herbicides are labeled to control this weed. However, in a lawn situation the best way to control them is to promote conditions ideal for your grass to grow. A thick healthy turf resists weeds and lessens dependence on chemicals.
Wild geranium invasion doesn’t particularly bother me, because once warm weather hits it more or less melts away anyway. Besides, it gives the deer something in the winter to eat instead of ornamental shrubbery.
Ted Manzer teaches agriculture in northeastern North Carolina.