The Coastal Gardener: Get in on the next big plant trend — dahlias

“Dahlias are back in fashion,” said the magazine title.

The topic of garden fashion may not be high on your conscious agenda, but I’ll bet you subscribe to more gardening trends than you may be aware of. Fifteen years ago, hydrangeas were only seen in grandma’s or, maybe even, great-grandma’s garden. Calla’s were about as hip as knitting. Then, over the past 10 years, both of these seemed to spout up all over the neighborhood.

Dahlias seem to be one of the next big plant trends. Maybe it’s the symmetry of their flowers, which seems to appeal to young, contemporary tastes. Maybe it’s their cheerful daisy-like appearance — a sign of optimism and happiness, in spite of trying times.

Whatever the reason, few flowers have the power to dazzle like dahlias. From its humble origins in Mexico, the dahlia is once again one of the most popular summer flowers. A wonderful characteristic of the dahlia is its versatility. Dwarf varieties stay small and are perfect for patio pots or low borders. Mid-sized varieties work as seasonal fillers or as closely spaced mass plantings. The giants, reaching up to five or six feet, are suitable for backdrops or deep flower beds.

The huge variety of flower shapes and sizes have added to the appeal of dahlias. Ball, cactus, anemone, pompon, decorative and peony are some of the descriptive flower forms available. Almost every flower color except true blue is represented. For gardeners who like their flowers big, the dahlia is one plant that can live up to the description of “dinner plate.”

If you have been attracted to dahlias recently, this is the time of year to really feed your addiction. Dormant dahlias in February and March are sold alongside lilies, gladiolus, tuberous begonias, caladiums and other “summer bulbs.” But dahlias actually grow from tuberous roots, not bulbs.

Although dormant dahlias should be planted in the next month or two, their local blooming season is mostly from early summer through fall — longer than almost any other summer flower. During this flowering period, the more you cut the blossoms and fill a vase, the more prolific they become. It is not unusual for a single dahlia to produce 50 to 100 flowers in just one season.

Dahlias are a little like roses — most gardeners can’t grow just one. Once you grow a dahlia, you want more. And there’s lots more, hundreds of hybrids. Like roses, there are seemingly endless dahlia selections to keep the gardener happy. Growing them is remarkably easy and can be quite inexpensive, if you start now. There are very few flowering plants that cost so little, yet give you a near constant supply of blooms all summer and fall.

Whatever dahlias you choose to plant, the process is the same, and now is the time to start, when the dormant plants are inexpensive and the selection is large. Pick a sunny area, with good air circulation and prepare the soil as you would for a rose or other large perennial, by adding an organic amendment.

Place the tubers, which look a bit like a small bunch of brown carrots, into this prepared soil. Lay the tubers horizontally, about four- to six-feet deep, then cover them with soil. Water the tubers once; thereafter just give them an occasional sprinkle if the weather is especially warm and dry, until sprouts appear above the ground. Watering too much will rot the dormant tubers.

Once the dahlias have sprouted to about six inches most gardeners will want to pinch their growth tips. This will encourage the fast-growing dahlia to branch and create a more full plant with more flowers. A second pinch can follow in another two or three weeks and will encourage even more branching. If you are growing tall dahlias (taller than about three feet), you will need to add stakes to help support the top-heavy plants and avoid a disaster on a breezy afternoon.

Any stake will do; wood or metal are fine, although I prefer the natural appearance of bamboo, and they’re easy to cut shorter if you need to. Don’t ignore this instruction. With a little effort, the stakes will be completely hidden by the attractive leaves. It’s best to insert these stakes at the time you plant the tubers, so you don’t damage the root when pushing them into the soil later on.

Fertilize dahlias as you would roses — frequently, with a balanced organic fertilizer that is slightly lower in nitrogen and higher in flower producing phosphorus. Dahlias root deeply, so water them thoroughly and deeply during our warm summer months. If possible, try to avoid overhead watering, which may damage the flowers and make plants even more top heavy.

In two or three months you’ll see potted, blooming dahlias filling all the nurseries and garden centers, and you’ll want every one of them, but savvy gardeners can plant the inexpensive dormant tubers now and enjoy the flower show all summer, at a fraction of the cost.

RON VANDERHOFF is the nursery manager at Roger’s Gardens, Corona del Mar.

Ask Ron

Question: When should I prune my clematis? I planted it last spring.

Allanis

Newport Beach

Answer: Most hybrid clematis that you are likely to have in a local garden are pruned about the same time as roses, usually January. But don’t worry, there is still plenty of time. For specific instructions on how to do this surprisingly easy chore, consult the popular Sunset Western Garden Book.

ASK RON your toughest gardening questions, and the expert nursery staff at Roger’s Gardens will come up with an answer. Please include your name, phone number and city, and limit queries to 30 words or fewer. E-mail stumpthegardener@rogersgardens.com, or write to Plant Talk at Roger’s Gardens, 2301 San Joaquin Hills Road, Corona del Mar, CA 92625.