Succulents Aren't Just for the Desert Anymore

If you're looking to diversify your product line and set yourself apart from the competition, perhaps you should consider growing succulents. They are adapted to withstand drought by storing water in specialized cells in their leaves, stems and/or roots. The term succulent does not refer to a plant family per se, but to a water-storing adaptation that is found in many different plant families. Cacti are probably the best-known family of succulent plants, but there are many other types in a huge variety of shapes and sizes.

Succulents are increasingly popular. With water restrictions in place across the country, there is an increasing demand for plants that promote water conservation. Many succulents are particularly well adapted to withstand climatic extremes, such as drought, heat, wind and frost. They are generally free from pests and diseases and are less prone to nutrient deficiencies. They are also tolerant of poor and shallow soils.

Growing A Succulent

Mixed containers of succulents are a high-value product that consumers love because they stand up to neglect. Even when they are not in bloom, many succulent plants provide visual interest in the form of bold textures and colorful foliage.

Although succulents may take longer to produce, they actually thrive on reduced water and fertilizer inputs; rarely require insecticides, fungicides or PGRs; and are easily propagated by stem or leaf cuttings, or produce offsets that can be removed and potted. Most succulents can also be propagated by seed, but it may take a year or longer for them to reach a salable size.

To grow succulents, you will probably need to modify your production protocol. A well-aerated and freely draining medium is critical. Commercial cactus and succulent mixes usually consist of equal parts coarse sand, perlite, peat or fine bark. To make your own, try mixing one part soil-less or soil-based media with one part coarse sand and one part washed grit, small gravel, claimed clay, pumice or expanded slate. Mixing a time-release fertilizer in the media will ensure a constant supply of nutrients. Succulents should be allowed to dry slightly between watering. Under potting is a good way to ensure that the roots don't become over saturated.

To produce rapid growth and the best form and color, succulents should be grown in the strongest light possible and warm temperatures, as they will respond more favorably to high water and fertilizer inputs. Many succulents tend to go dormant during the shorter days and cooler temperatures of winter. This is the time when they are most prone to fungal pathogens that cause rot. To keep them actively growing during the winter months, extend day length with supplemental lighting and keep your greenhouse warm. Maintaining a lower-than-normal relative humidity and excellent air circulation will reduce the likelihood of disease and pests.

Agave

The century plant, or agave, is an incredibly diverse group of rosette-forming perennials. There are agave to suit almost every U.S. climate, with cold hardy forms that can withstand single digit temperatures. While most people look at these plants as a Southwestern phenomenon, our changing ideas of annual are opening markets as summer color throughout northern United States. Growers may need to look at buying in pre-finished material, this is a very slow crop from seed to sale -- 1-6 years. Plants are durable but heavy, which can be a problem in shipping.

Another misconception is that all agave are sharply spined and a problem to work with; while it may be true for most, one of the most dramatic and easily grown species, A. attenuata, is soft leaved and extremely architectural. There are agave native throughout the United States, and for specimen containers, you can't beat these prehistoric, bold textures except by using paddle Cacti, which is also a great idea, but will have to be another article...

Sempervivum and Echeveria

Sempervivum and echeveria are both commonly known as hens and chicks. Sempervivums, also referred to as houseleeks, are native to southern and central Europe. They are generally frost-hardy but tend to suffer in extremely hot and dry conditions. The leaves form low-growing, tightly rounded rosettes in varying shades and patterns of green, gray and red. The flowers, usually pink or purple, are held just above the foliage. These plants are monocarpic, which means that each rosette dies after it flowers, leaving behind a cluster of offsets. There are approximately 40 species and at least twice as many cultivars of sempervivum. The most commonly grown and hybridized species are S. tectorum, which has gray-green leaves with red tips, and S. arachnoideum, which has tiny threads connecting the leaf tips to create an amazing cobweb effect. Sempervivum are appropriate for landscape use throughout most of the United States but are prone to rotting in areas with hot, humid summers.

Echeverias are native to Central America. Consequently, they are able to withstand high temperatures and drought better than their European relatives but are not particularly frost-hardy. The rosettes of echeveria are generally much larger than those of sempervivum, and the range of leaf shapes and colors is much more diverse. The foliage colors include green, gray, blue, pink, orange and red, and many are edged in a contrasting color. Some echeveria have leaves covered with soft downy hairs, but most have a powdery or waxy surface that lends a shimmering richness to the foliage. The bell-shaped flowers, in yellow, orange, red and pink, are borne in clusters on arching stems.

There are about 150 species of echeveria, which have been extensively hybridized to create an astounding assortment of cultivars. E. lilacina has powdery gray leaves with pointed tips, forming a tight, elegant-looking rosette. E. shaviana has blue-green glossy leaves with frilly edges. One of the most popular cultivars is 'Perle von Nurnberg', which has broad, pointy-tipped, gray-green leaves flushed with pink.

Euphorbia

The genus euphorbia has more than 2,000 species (commonly called spurges), about half of which are succulents. Poinsettias and crown of thorns are two of the best known euphorbias. Characterized by tiny petal-less flowers enclosed by brightly colored, showy bracts, all euphorbias should be handled with caution because their milky sap (known as latex) is irritating to the skin and mucous membranes. Some spurges, such as E. horrida and E. echinus, are leafless but have swollen spiny stems that resemble a cactus. Others, including E. obesa, form small rounded, ridged domes that might be mistaken for sea urchins. The crown of thorns, E. milii, has erect spiny stems with showy red bracts. New crown of thorn hybrids, Euphorbia x lomi, have much larger, longer-lasting bracts in a variety of colors.

All of these species are generally grown as container plants, but many succulent spurges may be grown as landscape plants in temperate zones. E. myrsinites has spirally arranged, gray-green leaves and clusters of greenish-yellow flowers. Gopher spurge, E. lathyris, has leaves with a white midrib and small green flowers and is reputed to repel burrowing rodents. The Mediterranean spurge, E. characias, grows to 3 feet, with erect woody stems, long linear leaves and dense showy yellow flowers. Many cultivars of this species, including a variegated form, are also available.

Sedum

There are several major groups of sedum with quite different growth habit. The stonecrops are a fantastic group with all of the foliage, flower qualities and textural interest you could possibly ask for. Most sedum are good ground covers in the landscape and easy in containers. They root from any leaf that breaks off and can be propagated in this way, by cuttings or from seed. S. acre is a great perennial ground cover with yellow flowers in early summer for the northern states, and S. spurium and its hybrids provide brilliant purple to red-toned flowers and are winter hardy. For the southern states, S. procumbens, S. rubrotinctum and S. mexicana perform the same role.

We trialed Sedum 'Angelina' from EuroAmerican this year, and it was outstanding for yellow-toned foliage and growth habit. Ball Floraplant's 'Coral Reef' and 'Sea Stars' were both fine-textured and dense-growing plants. Another great group of sedum to try, which has excellent Northern hardiness, is S. spectabile. These are upright forms with fall flowering, usually in shades of brownish burgundy to red. 'Autumn Joy' was the old standard and is still readily available, but look for purple foliage forms ('Purple Emperor'), variegated foliage and dwarf types ('Mini Joy').

There are literally hundreds of sedum species and cultivars out there, and they make outstanding landscape or container plants, with extremely low water requirements. I couldn't begin to cover all of them, but you can do an Internet search to find some that work for your operation.

Succulent Mixed Containers

I was so pleased to see that Saul Nurseries', Atlanta, Ga., booth at the Southeast Greenhouse Conference had some excellent examples of succulent mixed containers. I really think more nurseries should look at this product as a way to diversify from chain retail. These succulent containers are heavy, fragile and don't ship well, giving local marketers a real edge. In following the old rule of one upright plant, one mounding plant and one trailing plant, try using agave or yucca for the upright plant; echeveria, euphorbia and kalanchoe make excellent mounding plants; and sedum or portulaca are trailing components. These containers are a bit slow, but easy and can be planted in anything -- old tires, moss topiary and wreathes, sea shells, driftwood or custom cement containers -- to make for unique and profitable retail sales.