For many years I tended to ignore the tropics as a source of plant material for our gardens, and cast my eyes towards cold places like northern Europe and Siberia with climates like ours. Plants that can acclimate and be naturalized here have long been my primary fascination; but, let’s face it, what would a gardener’s life be without melons, squash, tomatoes, peppers, corn, beans and so on – all of which require (here, at least) the hand of a gardener to grow and to propagate.
The question becomes how much energy, space, time and treasure does any particular plant require, and is what you get out of it worth the input? I am quite willing to start peppers and tomatoes early on a kitchen window sill and hand-pollinate squashes. They’re definitely worth that much to me, but, for instance, I wouldn’t go so far as to buy plastic mulch, build hoop houses, etc, at least not at this point in time. This is all to say that I am quite delineated about how much space, time, energy and treasure I am willing to allocate for a given plant.
Tomatoes and peppers were originally perennials from the lower latitudes, but we have adapted them to grow as annuals and be productive nearly all over the globe. So, from that perspective, there are no doubt other valuable tropical plants that can acclimate to our gardens, even in northern Vermont, without too much fuss.
Ashwaganda (Withania somnifera)
A few years back I started hearing about gardeners in similarly cool climates growing herbs from India, particularly ashwaganda and tulsi, so we cautiously trialed some. We’ve had significant success with three of the primary ingredients for chyawanprash, which is now part of our daily diet, and consider these permanent members of our plant menagerie.
Ashwaganda is a perennial nightshade, a relative of peppers and tomatoes, and is grown pretty much on the same schedule – here it must be started early indoors and transplanted out after danger of frost is past. It is more frost tolerant, likes drier conditions and requires less fertility compared to tomatoes and peppers.
We use the root dried and in chyawanprash, and were thrilled last season when, out of the 18 plants we had growing, one set fruit, and viable seed. None of the others showed any sign of even flowering, so this was exciting and promising for it to adapt as an annual here, maybe even to naturalize (though I do not know how freeze tolerant the seeds are). Now we are growing out the seed from this very early individual, and expect to develop our own short season strain. On trial for this season we also have a strain from Africa purported to have high vigor, so maybe it will throw some early fruits, too.
A young tulsi plant
Tulsi, or holy basil (Ocimum sanctum) is simply a lovely plant to have around, never mind that, like ashwaganda, it is an adaptogenic herb. In its native India, it is perennial and grows big enough for the stalks to be made into mala beads. It is ubiquitous at the entrances of homes and temples. Its fragrance is strong and uplifting.
A tulsi mala. (Tail of Arjuna the cat in the background.)
Although I have long grown numerous types of culinary basils, I never was able to get a good seed set from any of them, and I assumed that basils in general were all as cold sensitive as Ocimum basilicum, which is even more cold sensitive than melons. I had resigned to having to buy seed for basil, and I never tried tulsi, figuring it would be even less cold tolerant than its cousins.
A visitor gifted us with a plant one season, and I was pleasantly surprised. When the more familiar annual basils bloom and go to seed, which they are apt to do here prematurely from cold stress, it’s all over. The energy withdraws from the foliage, and the plants decline quickly, becoming an illustration of the term “gone to seed” used as a negative description. Tulsi sustains blooming and seed set, and continues to make new leaves and stalks. It dosn’t blacken at the slightest touch of frost either.
Tulsi actually sets seed well,
despite our short growing season.
Since we can get seed reliably from it, and grow it as an annual, it’s actually a sustainable plant here. I sow it about 4 weeks before the last frost, the same as the other basils, and set them out into warm soil. Because we don’t have a greenhouse or cold frame, window sill space for growing transplants is at a premium. I discovered that all the basils do very well sowing fairly thickly into 2 inch pots, and leaving a dozen or so seedlings in each pot. While it’s not as ideal as sowing into plugs or something like that, the seedlings do fine as long as they are transplanted fairly promptly when the time is right.
Brahmi in its winter quarters.
Our third import from India is brahmi, Bacopa monnieri. It is similar in some ways to another herb from India that I have had a great interest in, gotu kola (Centella asiatica). They both have been used medicinally to support healthy brain function, and both are swamp plants. I didn’t know of brahmi until recently, but had tried several times to grow gotu kola without success. I like using gotu kola enough that I was willing to pamper it as a houseplant, but it was impossible to keep the surrounding air humid enough for it, even in a terrarium.
Brahmi, on the other hand, is perfectly happy as long as its feet are wet. It summers in a pot set into a wet garden bed, where it spreads rampantly. In the fall, a piece can be put in a 4 inch pot to winter over on a kitchen window sill, as long as the pot is kept wet. Just that much is quite adequate for two people to nibble off daily sprigs throughout the winter, and have a good sized plant to set out in the warm weather. Brahmi is perennial in India. We have gotten some flowering but I’m not sure about seed set – the seed capsules are tiny, and while some capsules formed, I could not tell if they any had viable seed, and I haven’t yet noticed any volunteers. That’s OK, though – it roots so easily there’s no need to bother with seed.