NEWBERG, Oregon—I’m surprised to see my newest sweet violet, Viola ‘Mrs. David Lloyd George’, again this fall sending up some flower stalks. In late winter and early spring, it had a heavy bloom period. Its semidouble violet flowers have a perfect center rosette of white with lavender surrounded by deep violet outer petals. In addition to the sheer beauty of its flower, the plant has the advantages of being long-stemmed, great nosegay material, superbly fragrant, and untroubled by spider mites during our hot summer. This violet was a chance seedling discovered about 1915; however, it disappeared from the English nursery trade and has only recently returned via Australia.
Farther along the garden path, I begin to see the telltale signs of the changing seasons. Both the angelica and lovage have yellowed, and their stems have toppled over onto the neighboring herbs. But I’m not too eager to clean up the garden yet, at least not entirely. I know that the weather is still wonderful to work in and that it is a pleasure to step out onto a crisp, clear, cold morning to be warmed by the rising sun and dazzled by the sparkling of heavy dewdrops dangling on the spider webs or the serrated leaf margins of my lady’s-mantles. Many people like to tidy up the herb garden before putting it to bed for the winter, but I’ve decided to take a different approach this year.
We all know gardeners who somehow manage to overwinter those borderline-hardy herbs (pineapple sage, lemon verbena, and so on) that routinely die on us. When they continue to overwinter those herbs successfully year after year, I have to face up to the ugly truth that they’re doing something right and I am not. Swallowing my pride, I ask them how they do it, but usually they don’t know. Finally, I found someone who does know why—beyond the classic answers of good drainage, southern exposure, raised beds, and so on. He speaks from experience and observation. I had the opportunity to attend a talk given by Tony Avent, a plantsman and nurseryman from North Carolina, where the climate is similar to ours here in Oregon. He suggested that many plants are hardier than the reference books stated—a suspicion a lot of us have—and that if we want to grow a plant we should keep trying. Certainly, plant hardiness zones are a generalization of large-scale climatic conditions and do not take into consideration the characteristics of our smaller microclimates. Tony’s advice on wintering over Mexican bush sage (Salvia leucantha) seems sound to me. It is reliably hardy for him if he does not cut back the dead stems in the fall. The stems are hollow; if you cut them off in the fall, the stubs will fill up with rain and then freeze during the winter, injuring the crown. This scenario may apply to many of the other tender perennial sages with hollow stems, such as S. discolor and rosebud sage (S. involucrata). One winter, my lemon verbena survived a week of 3°F. At the time, I attributed its survival to the excellent drainage I had provided, but on second thought, I may have neglected to prune off the dead canopy. I also find that eliminating weeds from the crowns of plants such as French tarragon increases winterhardiness immensely because weeds trap moisture around the crown and make it more susceptible to freezing.
Unfortunately, the truly tender perennials such as lemongrass must come inside to survive. As I step into my greenhouse, I see that my aisles have narrowed considerably with rows of one-gallon pots of stock plants and specimen herbs. I didn’t realize that I had collected so many plants over the year from plant sales, mail-order nurseries, trades, and gifts. It looks like an herbal jungle, but I must say that I am rather proud of myself for sowing about 90 percent of all those interesting seed packets I ticked off on this year’s seed lists. Now, if I only had a larger greenhouse to house my new plants!