A “volunteer” plant is defined as one you did not intentionally start from seed or transplant. Often. these volunteers perform better than plants purchased or started from seeds. Occasionally, you regret their arrival.

 When I moved two years ago, I accidentally brought dormant seeds of Petunia integrifolia along with my potted Peony bulbs. This wild petunia (not to be confused with Ruellia, which also goes by the common name Wild Petunia) is an ancestor of the cultivated variety we buy today. My husband calls them “granny petunias.” In flower shades of purple, these lax plants spread themselves about with wild abandon. In a single season, they have inserted themselves between every one of my 50+ Peonies and even marched downhill to pop up in random areas of my small orchard. I allow these gratuitous plants to remain wherever they place themselves because (1) they flower a long time and add a lot of color, (2) the foliage has a fragrance and sticky texture that encourage critters to leave it alone, (3) they ignore heat and drought, and (4) even if plants die due to neglect, they usually drop seeds that will germinate and rapidly grow to flowering size, meaning the show goes on for months and months, with no encouragement from me. If they grow too lanky, a severe cutback will generate new growth and renewed flowering. Due to their unkempt growth habit, these plants look better from a distance.

Brown-eyed Susan seeds (Rudbeckia triloba) hitchhiked to the new location in pots of purple Coneflower. When young, the Susan’s foliage mimics Coneflower (Echinacea) so closely that I did not realize their separate identity until they began flowering. They share the same cultural preferences as the Coneflower, and are in full bloom right now. I have transplanted a dozen or so, and given away twice that many. A native heat-lover that is perennial in zones 4-9, the yellow flowers are a pollinator favorite. They make long-lasting cut flowers.

I am uncertain of the origin of native annual Spider Flowers (Cleome hassleriana) which arose in an area that was heavy woodlands before land clearing that took place in March of this year. A single plant appeared in May and was covered with flowers. Three more plants emerged nearby in June but one of these was decapitated, although whether by animals or human means is unknown. As dusk approaches, giant Sphinx moths (look like fuzzy hummingbirds) visit to sip nectar. Older varieties of Cleome will reseed heavily. Newer introductions are both shorter (two feet tall versus five feet of older generations) and sterile, so reseeding is not a concern.

Finally, Perilla frutescens made the move from old garden to new. I love the ruffled purple foliage of this mint relative but the reseeding is insane. Flowers are inconsequential, but the foliage makes a great vase addition, especially when paired with pink flowers. Once flowering begins, I remove and discard them, leaving only a single plant to ensure I have some for the following year. Many friends have asked for a transplant, and then berated me soundly after they ignored the advice to remove it before seeds started to drop. More than once, I have heard, “How could you have given me such a thug? That **** is everywhere!” Years ago, I was speaking to a garden club on unwelcome volunteers. I brought examples as visual learning aids. When I held up the example of Perilla and said, “If anyone gives you this plant and tells you that it is purple Basil, that person is NOT your friend.” There was an uncomfortable shifting in the seats and some averted eyes. I knew that I had touched a nerve somehow, but it was not until after my presentation was over and the meeting concluded that I learned the source of disquiet. One of the members walked me to my car and shared that the club president had given each person a Perilla plant the prior meeting, telling them that it was purple Basil. Oopsie! Let’s assume she was ignorant and not evil.

Herein is the rub. A few plants that arrive as volunteers are like guests that just won’t leave. Perilla, above, is one of them. Pink Evening Primose (Oenothera speciosa) is another. Before you allow a volunteer to remain in your garden, do a little research to be certain it will not displace better-behaved specimens. An additional caution: Vegetable plants that arise from seeds dropped the prior year may look like their mother plant but not taste the same. The curcubits (squash, pumpkin, melons, cucumbers) are prone to producing volunteers with bitter or tasteless fruits. If the fruits of a volunteer do not look or taste the same as their mother plant, do not eat them. Pull the plant and discard it. Tomato plants frequently arise where seeds fell the prior year. (I am super guilty of not harvesting rotten or split tomatoes.) If the mother plant was a hybrid, its offspring will not have the same benefits of hybridization. Volunteer tomato plants may be less disease-resistant, and fruits may be less flavorful and more prone to splitting, cat-facing, hard green spots, etc. I am pleased to report that my favorite cherry tomato, ‘Camp Joy,’ comes true from dropped seeds each year. The vigorous, indeterminate plants set an enormous number of quarter-sized fruits with real tomato flavor, acidic enough to be tasty with none of that too-sugary sweetness.

Enjoy your volunteers – but make sure they are polite keepers.