BOULDER – For a remote island chain, Hawaii gives gardeners a lot to be grateful for beyond floral shirts, coconuts, and pineapple slices. The westernmost state in the union keeps us dreaming of lush plant paradises, complete with waterfalls, wildly colored birds, and warm weather.
The Aloha state came by its diverse botanical denizens via makani (wind), moana (ocean), and manu (birds). Humans introduced many plants to the islands that are mistaken as native plants, including the iconic pineapple (native to Brazil and Paraguay) and the heavenly perfumed plumeria (central and south America). But a few true natives have found their way into our homes and hearts as house plants we love in winter.
ʻĒkaha, or the Bird’s Nest Fern (Asplenium nidus) is a slow growing plant that is perfect for the low light in our homes. Named for the tight clump-like rosette the spear-shaped fronds grow from, these ferns are easy to grow. An epiphyte in its native Hawai’i, it can be grown in a shallow pot in a peat moss-based medium.
ʻĒkaha should be placed away from direct sun in a location that doesn’t get drafts. Keep the soil moist but not soggy. Provide a humidity tray for moisture around the plant and fertilize it with 13-13-13 slow release fertilizer every six months. Trim off browned, older leaves.
ʻŌkupukupu Sword Fern (Nephrolepis exaltata) is a commonly found fern with pinnae, feathery fronds that curl up from the soil. ʻŌkupukupu is the original parlor fern, perfect for pots or hanging baskets.
Repot these ferns every year or two to avoid them becoming root bound. ʻŌkupukupu develop runners from which plantlets sprout; to propagate, just remove the plantlets once they’ve developed a few fronds and pot into soil. Fertilize like ʻĒkaha, or foliar feed with fish emulsion. Keep the soil moist but not soggy.
As a rule of thumb, low-level light rarely strikes the leaves and typically comes from north facing windows. Medium, or indirect light, is when light strikes the foliage for less than four hours per day. Through winter, medium light comes from east and west facing windows.
No thought of Hawaii is complete without Aloalo, the hibiscus. Several species are native to the islands and the state flower is Pua Aloalo, the yellow hibiscus (Hibiscus brackenridgei). The woody shrub typically sports the showy flowers with extended staminal column depicted on shirts and decals.
Aloalo need high light to thrive, so lighting that produces 1200 foot-candles is required. To accomplish this, pick up a 125-watt daylight CFL bulb with a hanging reflector from a local grow store or put them in a sunny window. High or direct light falls across plants for a minimum of four hours daily.
They prefer drier soils but not completely dried out; check soil moisture before you water. Flowers form on the tips of new branches, so prune them to keep them bushy in early fall. Fertilize every two weeks in spring and summer, then once monthly in winter.
The dry interior of homes is stressful to many houseplants. Although misting the foliage is one way to approach this, an easier approach is to place a pebble tray filled with water under the plant.
Simply take a tray and layer small stones evenly along the bottom, then fill with enough water to reach the top of the stones. Place potted plants on this tray, but take care that the water is not touching the pot itself. Most houseplants should not be placed in standing water.
Refill the pebble tray often to keep the humidity levels even, and group plants closely together. In general, most houseplants like temperatures between 70 and 80 degrees during the day, and above 60 degrees at night. If you lower your thermostat during the day, put all of your plants in the warmest room of the house.
Colorado State University Extension, together with Boulder County Parks and Open Space, provides unbiased, research-based information about consumer and family issues, horticulture, natural resources, agriculture and 4-H youth development. For more information contact Extension at the Boulder County Fairgrounds, 9595 Nelson Rd., Box B, Longmont, 303.678.6238, or visit ext.colostate.edu/boulder.
By Carol O’Meara, Colorado State University Extension, Boulder County