Convertible Plants for In or Out

            With March on the horizon it is time to decide which new plants are essential to revitalize your garden and it is also the time of year when you are more than likely to toss your inside plants outside! Because I really don’t have a good place for houseplants the few I have are refugees from summer or gifts.

            Three pretty potted coleus plants grew from gift cuttings, giving a head start to future pot combinations. Another gift is a Thanksgiving cactus leaning into a southern exposure and asking to be taken outside. Both the plants and I prefer to be outside, but must await spring. Another summer leftover is the pelargonium on the garage floor by the furnace. It has had a bloom on it all winter despite not having had a drop of water: I am itching to cut it back and put it outside.

            I have been expecting it to go dormant but it is like an exhausted toddler who refuses to take a nap because he’s ‘not tired’. These tender geraniums are perennials but we treat them as annuals because they are so sensitive to frost. Their blooms are a brilliant burst of color for window boxes or pots but it is their foliage that is a special delight. In some varieties it trails and in others it sports zonal markings or a silver edge and best of all is the fragrance when the leaves are rubbed, rose, pine, even peppermint, fragrances that do not appeal to rabbits or deer. Pelargoniums love full sun and do not need to be watered until the soil is totally dry, very adaptable!

            Some of the most interesting plants are those that quite properly belong to zone 8 but do fairly well in our zone 7. Michelia figo or banana shrub is a large handsome evergreen hardy in zone 8 that is often sold as a houseplant. When I bought one on the Outer Banks ten years ago I was told it would top out at four feet and that it was a native. Planted outside, it is way over my head, kept that height by judicious pruning, and it is a member of the magnolia family native to Southeast Asia.

            The only reason for the ‘banana’ name is that the pretty cup-shaped flowers do have a pleasant banana fragrance. Possibly if it were kept as a houseplant it would stay small. The real banana, Musa, has become popular for its huge leaves. A small grove of these suckering stems is a tropical statement! The musa basjoo, the Japanese banana, is hardy in zones 8 to 10 so could be grown here in a sheltered spot. Musa acuminata ‘Siam Ruby’ has reddish bronze leaves and grows to 8 feet but if kept in a pot it stays smaller. It would have to share your living space for the winter and you would also have to continue to buy bananas at the grocery.

            For both fruit and foliage there is Musa x Paradisiaca. Although it grows only 4 feet tall in a pot, it produces delicious 4-inch bananas in 10 pound bunches. It will stay small enough to winter in the kitchen. This super dwarf banana needs good light, good drainage, water, and high potassium fertilizer every few months. It is self-fertile so you won’t need a plantation, just a plant. You may have guessed that it needs potassium (the third number in 5-5-10 fertilizer) since people who suffer from a potassium deficiency are diligent about eating potassium-rich bananas.

            Another plant, hardy only to 45 degrees, too tender to leave outside all winter is Plumbago auriculata, Cape leadwort, an evergreen shrub grown as a climber. It is treasured because it is that color rare in the plant world, true sky blue! The abundant flowers resemble those of a phlox. One cultivar of this South African plant, ‘Imperial Blue’ is a deeper blue than the original. In the same plumbaginaceae family is the Ceratostigma, a charming blue-flowered  ground cover grown easily by friends but refusing to last in my garden. A shrub in this family is hardy in zone 8 and in both species the leaves turn red or bronze in autumn. C.willmottianum, Chinese plumbago, is a deciduous shrub hardy in zones 6 to 9 and grows to 3 feet.

            I have an unrequited love for Penstemons: the dark foliaged white flowered ‘Huskers Red’ is the only one that stayed with me for more than a season or two even though I tried to make sure they had excellent drainage and sun. High Country Gardens Nursery specializes in them and has a new beardtongue, Penstemon ‘Blue Lips’ an evergreen hybrid with blue-lipped lavender throated flowers on blue-grey needlelike foliage. I do know that Penstemons do well in dry climates but in Tidewater our humidity  is high even during drought. Is that my problem?