Weed Rant: Horse Nettle

It is time for another weed rant. Horse nettle, Solanum carolinense (pronounced so-LAN-num kair-oh-lin-EN-say), is number two on my list of Weeds From Hades. (Number one is mulberryweed. Click HERE to review A Terrible, Horrible, No Good Weed.) Horse nettle has two, and only two, positive attributes. It is southeastern native, and bumblebees love the pale lavender flowers. If I was feeling generous toward this plant demon (I’m not), I could add that wild turkey, quail and a few songbirds enjoy the berries. The berries and all other parts of the plant are seriously toxic to humans, pets, and livestock.

Horse nettle is found in more than half of the USA. It is a tap-rooted perennial that will grow in any type of soil and any pH. It grows along sunny roadsides, in open fields, and in cultivated gardens. I thought that tilling the soil in my orchard would vanquish this foe, but instead the tilling process broke the root and its fleshy rhizomes into pieces, all of which returned with a vengeance. I do not use herbicides in areas where food is grown, so the only method of removal is digging and pulling. The razor-sharp prickles penetrate thin garden gloves, so I have added a pair of cheap pliers to my bucket of garden tools. I grasp the base of the plant with the pliers and lift gently, while using a tool in the other hand to loosen and lift the rhizomes that radiate off the tap root. It is a slow process, better done after a rain has softened the soil. [Side note: Prickles are modified plant hairs, spines are modified leaves, and thorns are modified stems. Roses have prickles, not thorns. Best not to mention this to poetry-writing friends.] Even if the prickles do not stab you, the star-shaped hairs cause misery when they brush against an unprotected ankle.

Young horse nettle leaves resemble tomato. Stems zig-zag and become woody with age. Plants may be 30 inches or more in height, but tend to sprawl rather than growing upright. They flower from spring all the way into fall. The fruits are round green marbles containing several seeds each. In late fall, the green fruits turn yellow and can be mistaken for a tiny tomato. Fully ripe berries wrinkle a bit. If you have children or grandchildren, please educate them about this plant. Ripe, yellow fruits are even more toxic than the green ones. Consuming them can lead to coma or death. Not only does horse nettle stab the careless gardener, it also plays host to tobacco hornworms and Colorado potato beetles.

If herbicide is your chosen method for eradication, check the label to be certain it is listed. Horse nettle is resistant to some herbicides (2,4D for instance) and repeated mowing has no effect.

Other common names for horse nettle include bull nettle, devil’s tomato, or apple of Sodom. The name of those in the Mary Snoddy garden is not fit for print.

Horse nettle flowers

Evil prickles

Immature fruit

Awesome Thorns - Hardy Orange

Every gardener has their favorites. I love anything with thorns. My friend Sallie labeled this peculiarity a Crucifixion Complex. Of the many choices available, Hardy Orange (Poncirus trifoliata) is high on my list.

Not a true citrus, this 15-foot deciduous tree is cold hardy in zones 6-9. The fragrant white blooms produce yellow-orange fruits a bit larger than a quarter. Some may be as large as golf balls. The aromatic fruit is filled with seeds rather than pulp. It should be considered inedible, since ingestion causes stomach pain and nausea. Skin contact can cause minor dermatitis to sensitive gardeners.

Trees are drought tolerant. They prefer full sun and will grow in almost any soil. My specimen was planted on our property by my husband’s grandmother. It had been overtaken by a spreading evergreen tree. I transplanted the scrawny whip to be a focal point in a perennial bed. It thanked me for its rescue by growing rapidly. The growth habit tends toward a few long, wild water sprouts. I prune it hard every other year to keep its size in check and to give it a more pleasing shape.

Pruning is an act of self-flagellation. The three-inch thorns are sharp. When I pruned this week, I wore an insulated jacket, padded ski gloves, safety glasses, and a construction hard hat from my father’s workshop. The thorns will penetrate ski gloves, so I handle each branch carefully. I burn the discarded limbs rather than composting them. The dead limbs take forever to decay. Even after a couple of years, the thorns are sharp enough to penetrate the tires of my farm tractor. (Go ahead – Ask me how I know this.)  The lethal thorns make the tree inedible to deer. It is also disease-free and insect-free in the Mary Snoddy garden. 

The USDA lists Hardy Orange as invasive in fifteen states that encompass the southeastern quadrant of the USA. It was introduced across the country in the mid-1880s as a potential rootstock, with the hope that tender oranges could be grafted onto it and grown in colder areas.  That combination was not successful.

I carefully harvest every one of the dropped fruits to avoid rampant reseeding. If you cannot make the commitment to restrict the plant from spreading, please skip it. Birds and animals distribute seeds and plants sprout across the landscape. This invasiveness is unfortunate, because it would make a dandy barrier to trespassers.  ‘Flying Dragon’ is the only selected cultivar. Its limbs are little more contorted than the straight species.

One way to restrict plant size and control invasiveness is to grow the plant in a container.  I maintained several for years until they became too unwieldy.

Why grow such a dangerous plant? Glad you asked! They offer endless opportunities for decorating. Yes, you read that right. The stiff thorns will support gumdrops that can change colors with the seasons. One year I cut branches and spray-painted them glossy black. I jammed the stems into ripe pumpkins and draped them with fake spider webs. Best Halloween Décor Ever.

Bare limbs seen against a winter sky highlight the impressive thorns.