Stevia develops sweet-tasting foliage that’s an excellent alternative to sugar or artificial sweeteners. Given enough moisture, this tropical plant thrives in containers or in the landscape. Just be sure to plant it where the soil drains well; stevia will not thrive in constantly wet soil and resents heavy clay. Avoid using high nitrogen fertilizers. In northern climates, move stevia indoors before frost hits and treat it like a houseplant.
Height: 1 to 3 feet
Width: 18 inches
Flower color: White
Seasonal features: Fall bloom, Summer bloom
Special features: Good for containers, Low maintenance
The care and feeding of Stevia
Stevia plants do best in a rich, loamy soil — the same kind in which common garden-variety plants thrive. Since the feeder roots tend to be quite near the surface, it is a good idea to add compost for extra nutrients if the soil in your area is sandy.
Besides being sensitive to cold during their developmental stage, the roots can also be adversely affected by excessive levels of moisture. So take care not to overwater them and to make sure the soil in which they are planted drains easily and isn’t soggy or subject to flooding or puddling.
Frequent light watering is recommended during the summer months. Adding a layer of compost or your favorite mulch around each stevia plant will help keep the shallow feeder roots from drying out.
Stevia plants respond well to fertilizers with a lower nitrogen content than the fertilizer’s phosphoric acid or potash content. Most organic fertilizers would work well, since they release nitrogen slowly.
Gathering Autumn Stevia Leaves
Harvesting should be done as late as possible, since cool autumn temperatures and shorter days tend to intensify the sweetness of the plants as they evolve into a reproductive state. While exposure to frost is still to be avoided, covering the plants during an early frost can give you the benefit of another few weeks’ growth and more sweetness.
When the time does come to harvest your stevia, the easiest technique is to cut the branches off with pruning shears before stripping the leaves. As an extra bonus, you might also want to clip off the very tips of the stems and add them to your harvest, as they are apt to contain as much stevioside as do the leaves.
If you live in a relatively frost-free climate, your plants may well be able to survive the winter outside, provided you do not cut the branches too short (leaving about 4 inches of stem at the base during pruning). In that case, your most successful harvest will probably come in the second year. Three-year-old plants will not be as productive and, ideally, should be replaced with new cuttings.
In harsher climates, however, it might be a good idea to take cuttings that will form the basis for the next year’s crop. Cuttings need to be rooted before planting, using either commercial rooting hormones or a natural base made from willow tree tips, pulverized onto a slurry in your blender. After dipping the cuttings in such a preparation, they should be planted in a rooting medium for two to three weeks, giving the new root system a chance to form. They should then be potted — preferably in 4.5-inch pots — and placed in the sunniest and least drafty part of your home until the following spring.