Sunday, November 8, 2015

Sumac – Roadside’s Rowdy Rhus

This time of year is when our native sumacs light up the roadsides with spectacular fall color. Any other time of year, these plants will not be noticed (or worse they will be removed as “weeds”). It’s a shame to see these plants so unappreciated. Let’s examine their qualities and perhaps we can convince a few people to let the suckering sumacs do their thing.

Smooth sumac (Rhus glabra)
I am speaking here of plants in the Rhus genus. This does not include plants with sumac as a common name such as poison sumac (which is Toxicodendron vernix) or stinking sumac (which is the non-native Ailanthus altissima). The sumacs that are native to Georgia include fragrant sumac (Rhus aromatica), winged sumac (Rhus copallinum), smooth sumac (Rhus glabra), staghorn sumac (Rhus typhina) and the uncommon Michaux’s sumac (Rhus michauxii).

Winged sumac (Rhus copallinum)
Of all these species, the two most likely ones you would encounter in Georgia are winged sumac and smooth sumac (easily distinguished from each other by the wings on the leaves of the first one). 

Both are large shrubs that spread by suckers and have striking fall color. The compound leaves have numerous leaflets. They also produce upright bundles of red fruits that birds adore, so without leaves they might be a bit hard to tell apart.   

Fragrant sumac (Rhus aromatica) on Stone Mountain

Fragrant sumac is a lowing growing shrub with only 3 leaflets and looks very similar to poison ivy. Like the other two species, the fruits are red although there are fewer of them. The red fruits help to distinguish it from poison ivy which has white berries. Like its Rhus cousins, fragrant sumac has great fall color too. In the winter, the presence of male catkins at the branch tips helps to identify it.

Beyond human aesthetics, sumac is beneficial to wildlife. During the growing season, at least 54 native moths and butterflies use it for a host plant for their eggs. The clusters of tiny flowers attract numerous pollinators. In the fall and winter, birds and small mammals eat the fruits.

Fruit of Rhus glabra
All 3 of these common Georgia species are tough, dependable plants. Their tolerance of average to poor soil makes them suitable for hard to grow areas and their suckering habits help to hold slopes and stabilize poor soils. 

While they might not be appropriate for a small garden except perhaps in a container, these adaptable shrubs can find a place in many larger landscapes. At the very least, let's hope they can continue to decorate our roadsides.

Smooth sumac on Lookout Mountain in North Georgia

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