Gardening in Dorchester: Summer flowering bulbs to plant now

By Laetitia Sands, Special to Dorchester Banner
Posted 5/1/22

Some people may think of bulbs as a spring thing, a glorious show which ends when the last tulip drops its pretty petals, when the final daffodil turns the color of ancient parchment. But some of the …

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Gardening in Dorchester: Summer flowering bulbs to plant now


Some people may think of bulbs as a spring thing, a glorious show which ends when the last tulip drops its pretty petals, when the final daffodil turns the color of ancient parchment. But some of the biggest and brightest blossom imaginable – even in a gardener's wildest dreams – come from bulbs that flower in summer and can be planted now.

Turk's cap lily produces bright orange and purple spotted flowers and grows four to six feet tall. An ornamental onion (allium) called Globemaster sports reddish violet flower heads the size of soccer balls.

The stars in waiting include dahlias, gladioli, lycoris, tuberous begonias, calla lilies, caladiums (known for their amazing foliage), crocosmias (which resemble miniature gladioli), cannas, ornamental alliums and more.

Many of them, categorized as tender bulbs, have the off-putting reputation of needing to be dug up in fall, before the first frost hits, and stored for the winter somewhere cool – but not too cold – and safe from hungry mice and other rodents.

But not all summer flowering bulbs require such treatment. Some are hardy. Some, benefiting from the less harsh winters in our region than in other parts of the country, will defy their description as tender and survive happily under a thick blanket of dried leaves or another natural mulch, particularly if planted in a sunny, protected spot.

A friend of mine in Cambridge planted bulbs that produced dazzling blue-violet gladioli. They weathered the winter in a south-facing flower bed, protected by garden mulch, and returned year after year.

At the other extreme, a cousin of mine in a far-off cold wintered country fell head over heels in love with dahlias, planted dozens of them in his small garden and thinks nothing of digging them up every winter before the snow arrives. Such work can be a pleasure for a truly besotted gardener.

Among the biggest and brightest blooming bulbs of summer, lilies pose a headache for someone writing about gardening. Some are hardy in most climates. They can be planted in spring and left in the ground year-round. Others are cold-tender and must be lifted before the first winter frost.

Take African lily (agapanthus) and calla lily (zantedeschia), for example. Evergreen African lilies are tender, while deciduous ones will survive winter outdoors if protected with a thick layer of natural mulch.

Calla lilies may be OK in winter or they may need lifting. A bulb book I consulted says they survive winter in zones 8 to 10. Our county ranks somewhere between zones 7 and 8. With climate change, calla lilies may be fine if left in the ground year-round, but I'd protect them just to be safe.

The best policy is to check carefully before planting a summer-flowering bulb so you know if it's a tender or hardy variety.

If you value fragrance, consider planting summer hyacinth or summer bells (galtonia), freesia and Abyssinian gladiolus (acidanthera bicolor murielae). Summer hyacinths produce 20 to 30 white, bell-shaped, fragrant flowers on three- to four-foot stalks in midsummer.

Freesias smell divine and bloom in any number of lovely colors. While most flower in winter or early spring, specially treated bulbs from Holland flower in midsummer. The plants stand one to 1-1/2 feet tall and their blossom measures two inches.

Abyssinian gladioli, native to Ethiopia, produce creamy white, scented flowers with red, purple or chocolate brown markings inside, often from August to October. They stand 1-1/2 to 3-1/2 feet tall, depending on the variety.

Tuberoses (polianthes) and various lilies are also champions of fragrance, along with some other flowering bulbs. But some lilies, while strikingly beautiful, smell of nothing at all. Read the labels carefully and do your research before buying and planting these beauties.

In general, most tender summer-flowering bulbs need full sun to flower well, meaning five to six hours of direct sun every day. If left in the ground year-round, count on eight to 10 hours of daily sunlight.

Adequate drainage in the area where you plant is extremely important because most bulbs will rot if planted in a wet place.

Dig a hole 2-1/2 to three times the diameter of your bulb deep, loosen the soil below the level where you plan to plant the bulb, add fertilizer, then cover it with a layer of soil so the bulb doesn't touch the fertilizer. Set the bulb upright in the hole and cover it with amended soil.

Usually you don't need to worry about watering summer bulbs except in dry weather. Then, water them once a week, soaking the ground thoroughly. And remember to look after them after they've finished flowering.

Summer bulbs adapt to almost any type of garden soil, if well drained. If they're going to go into heavy clay, lighten it up first with organic matter. Lilies, in particular, hate to have wet feet within their root zone, which can descend as much as two feet below the surface. They may need to be planted in raised beds, eight inches to a foot above the surrounding ground.      

Strong wind poses a danger to taller bulb plants, so plant them in the lee of a house, garden wall, or group of shrubs or trees that will protect them from the prevailing winds. But don't put bulbs so close that they'll be in heavy shade.

In windy places, stake plants that grow more than three feet tall. Put the stakes in the ground when you plant the bulbs so as not to damage the roots that develop later. When plants reach two thirds of their full height, use soft green garden twine or plastic covered wire to tie them gently to the stakes. Tie just above the stem's halfway point and a few inches below the lowest blossom. Tie the twine tightly to the stake but loop it loosely around the plant twice, so as not to constrict the stem.

By the way, I heard a hummingbird for the first time this year, twice, as I sat writing this column on my deck. Happy gardening!

Laetitia Sands is a master gardener in Dorchester County.