Bulbs for summer bloom

'Tropicana' cannas                                                                                  Tesselaar

'Tropicana' cannas                                                                                  Tesselaar

We look forward to the bulb flowers of spring as a matter of course – the daffodils, tulips and crocuses that usher in the new season. The bulbs of summer are less familiar but no less delightful.

Cannas and callas and “glads,” oh my. Begonias and tuberoses. Dahlias and caladiums. Elephant ears and pineapple lilies. Nerines, crocosmia and gloriosa. There’s a whole array of tender (i.e., not cold resistant) plants to enjoy in the steamy days of summer.

It’s a convenient shorthand to call these “bulb flowers,” although technically speaking, they grow from corms, tubers and rhizomes as well as from true bulbs, which resemble onions in their layered structure and papery outer skin. These are all underground storage units that with nearly foolproof reliability produce a plant and/or flowers in fairly short order.        

The critical difference between spring and summer bulbs is the temperatures each requires. While spring bulbs like tulips and daffodils come from northern climates and need a period of cold to bloom, most summer bulbs are hot-blooded tropical natives that shrink from a chill.

Hailing mainly from South America and Africa, this group of plants includes some that can give the yard a touch of exotica, with outsized flowers and color-splashed leaves. Many are native to the tropical understory, growing in the shelter of leafy canopies, and so make excellent subjects for shade gardens.

Since the essence of the plant can be held in one hand and the root mass remains compact, bulb flowers are ideal container plants and often at their best when somewhat pot-bound. They can be moved around easily from season to season, too, with no staggering root ball to dig up lug around.

So, what’s the downside? Why aren’t these plants in every garden? It’s probably the need to set them out in spring and dig them up in fall that puts many off. Rule #1 is that you can’t leave summer “bulbs” in the ground over the winter if you hope to see them again. Freezing temperatures will reduce them to mush.

What this means is that you will have to harvest and store your dahlias and gladioli or stash in the basement your pots of cannas and colocasia, cut back to nubs. For some, it’s a chore too far. But since many summer bulbs are cheap (50 cents or less apiece) you can also write them off, treating them as flowers of a season like annuals, and buy more next year.

If there is a Rule #2, it has to do with providing good drainage, in the pot or in the ground. While a few species like canna can thrive with wet feet, most will rot in soggy soil. Water them generously since they tend to grow fast, but don’t let them become waterlogged. In pots, where watering tends to leach away nutrients, treat these plants to frequent doses of dilute fertilizer for peak performance.

Acidenthera                                                            Jindrich Shejbal/Flickr

Acidenthera                                                            Jindrich Shejbal/Flickr

Most gardeners are familiar with dahlias, a flower of many forms, with the tall spears of gladiolus, with the stately lilies and the brilliant tuberous begonias. Here are seven more unusual summer “bulbs” to try:

Acidenthera: The “Abyssinian gladiolus” has fragrant, star-shaped white flowers with a purple inner splotch that dangle gracefully, one per stem.

Caladium: A superb foliage plant for the shade with color-splashed, heart-shaped leaves.

Canna: If towering 6-footers leave you cold, try dwarf varieties, which grow to about three feet and are available in gentle shades of apricot, yellow, pink and peach. Cannas with brilliantly variegated leaves can be grown for foliage alone.

Crocosmia: A late-bloomer with thin, gracefully arching stems studded with brilliant red, orange or golden blossoms. Good for cutting.

Eucomis: One look and you will know why it’s called the pineapple lily. A real character plant for containers.

Gloriosa lily: Growing on a vine that reaches six feet or more, it bears exquisite, flame-colored flowers. Think Dutch still life.

Zantedeschia: Calla lilies now come in yellow, pink, orange and mahogany, as well as the original flawless white. Leaves can be stunningly dappled, too.



Brent and Becky’s Bulbs, 7900 Daffodil Lane, Gloucester, VA 23061. Call 804-693-3966 or visit brentandbeckysbulbs.com.

Old House Gardens, 536 Third St., Ann Arbor, MI 48103. Call 734-995-1486 or see oldhousegardens.com.

W. Atlee Burpee, 300 Park Ave., Warminster, PA 18974. Call 800-888-1447 or visit burpee.com.