Grow gladiolus from seed

Propagating Gladiolus Corms And Gladiolus Seed Germination

Like many perennial plants, gladiolus grows from a large bulb each year, then dies back and regrows the following year. This “bulb” is known as a corm, and the plant grows a new one right on top of the old one each year. Some of the more spectacular gladiolus flower bulbs can be expensive, but once you know how to propagate gladiolus, you can create an endless supply of copies for free.

Gladiolus Propagation Methods

There are two gladiolus propagation methods: germinating seeds and growing new plants from divided corms. The method you choose depends on how many flowers you want to grow and how much time you’re willing to invest.

If you want to grow a great number of gladiolus plants and don’t mind spending a few years doing it, gladiolus seed germination is the way to go. Leave the flowers on the stem for about six weeks after they die off. You’ll find a hard casing that is filled with seeds. Sprout these seeds into miniature plants and you’ll have full-sized gladiolus in about three years.

For quicker results with fewer plants, try propagating gladiolus corms. Dig the corms up at the end of summer for storage. Each corm will have a number of baby corms, known as cormels or cormlets, attached to the bottom. When you remove these cormlets and plant them separately, they’ll grow to flowering size in a couple of years.

How to Propagate Gladiolus Plants

Plant the seeds about six weeks before the last frost in the spring. Plant one seed in each 4-inch pot filled with potting soil. Cover the seed with a dusting of soil, water it well, and cover it in plastic. Remove the plastic when the seed sprouts and put the pot in a sunny spot. Grow the plant outdoors in the pot for the first year, then dig up the corm and store it. Plant the small corm outdoors the next two years in a row. By that time, it will be large enough to produce a flowering spike.

Dividing gladiolus bulbs for planting starts in the fall. Dig up each corm and remove the small cormlets from the bottom. Store them over the winter and plant them in the spring. The cormlets will grow into a plant, but won’t produce a flower this first year. Dig them up for storage at the end of the season, then replant them again the next year to produce flowers.

The Garden of Eaden

Gladioli have been out of fashion for many years now and that is a good thing. Why? Because that means the growers haven’t been growing them, so I haven’t been selling them and now that I have them in the garden they are effectively a brand new plant for me. (I accept that they have always been available as pre-packed bulbs, but a picture on the packet is no substitute for seeing the real thing in full flower).

Image credit – Claude Monet

AND WHAT A FLOWER IT IS! Let’s be honest, when it comes to mid-summer flowering plants you won’t be faced with much of a selection at your local plant retailer. So how can anyone in their right mind ignore the delights of this outrageously, flamboyant summer flowering bulb? Especially when it does what it does so well.

Gladioli are native to Mediterranean Europe, Asia, Tropical Africa and South Africa, but to be fair the center of diversity is located in the Cape Floristic Region, where most Gladiolus species were discovered. They are considered half-hardy in temperate climates, and grow from rounded, symmetrical corms, that are enveloped in several layers of brownish, fibrous tunics.
The spectacular giant flower spikes that we see in cultivated varieties are the result of centuries of hybridisation. The flower spikes are large and one-sided, and coloured, pink to reddish or light purple with white, contrasting markings, or white to cream or orange to red.
Growing Gladioli from seed

Image credit – http://www.thisgardenisillegal.com/

Gladioli seeds can be sown in February or early March, Sow them into seed trays containing a mixture of 5 parts loam, 4 parts well decayed leaf-mold, and 1 part well rotted compost. Alternatively, use a good quality seed compost such as John Innes ‘No 1’. Add a generous sprinkling of bone meal and just enough horticultural sand to improve drainage.
Sow the seeds thinly and shallowly, gently water and then place the seed tray in a warm, bright position such as a heated greenhouse or warm windowsill. They will need to be kept at a temperature of between 7 – 13 degrees Celsius where the seedlings should emerge four or five weeks later.
After germination the gladioli seedlings can be transferred to a cold frame. During the first fortnight in June the seed trays can come out of the cold frame and sunk into the ground so that the compost level in the seed tray is the same as the soil level. They will be happy in sun or partial shade at this point.
Keep the roots moist and feed moderately with a liquid feed over the summer. In the autumn, and once the foliage has died back, the corms can be lifted. Remove any compost and dry off so that they are ready for storage. They will then be ready for replanting in the following spring.
For related articles click onto:
HOW TO GROW GLADIOLI
HOW TO GROW GLADIOLI FROM SEED
HOW TO GROW GLADIOLUS MURIELAE
HOW TO GROW RUDBECKIA FROM SEED
WINTER ACONITE – Eranthis hyemalis

Surprisingly Hardy Glads

How Winter-Hardy Are Your Glads? Our Newsletter Readers Report

Although most references say gladiolus won’t survive winters north of zone 8, we kept hearing from customers that their glads were returning in zones 7, 6, and even 5. What’s more, these weren’t just Byzantine, ‘Boone’, or ‘Carolina Primrose’ glads — all of which we’ve found to be reliably hardy in zones 6a and warmer. These were “regular” glads they were talking about.

In zone 6a Concord, Massachusetts, for example, Jane Murphy wrote, “Some of the overlooked gladiolus bulbs I left in the garden last winter flowered this year, including a lovely ‘Spic and Span’ in October.” Kathi Frank of zone 5b Onsted, Michigan, emailed us, “I just have to tell you my joy when my ‘Atom’ glads survived the winter and came back this summer as beautiful as ever. What a bonus!” And Meredeth Allen of zone 5b Francetown, New Hampshire, called to say she “always” leaves her glads in the ground and “they come back every year.”

Then our good customer Bill Killpatrick of Lafayette, New Jersey, made a request. “I’d love it if you’d ask your newsletter readers about glads,” he wrote. “I’m just getting too old and creaky to dig ’em all up. Find it easier to just buy new every spring. But, much to my surprise, for the past four winters, a good 80% of the corms have wintered over just fine right in the garden. Officially, I’m in zone 6, but it’s a cold zone 6. We’ve NOT had reliable snow cover, I don’t mulch, nuthin’. But come spring, up pop the glads — big, double-corm, monster glads.”

So we asked our readers, and we heard from many in zones 5 through 7 whose glads over-winter in the ground and come back like perennials to bloom year after year. How can that be? Here’s what they said, along with a few possible explanations.

Warmer, Shorter Winters

The biggest factor may be that winters have been getting warmer. It’s not just that the average lows aren’t as low but also the cold isn’t lasting as long. As a result, the ground doesn’t freeze as deeply, and any corms that don’t freeze will usually sprout in the spring.

In 2012, the USDA updated its Plant Hardiness Zones Map for the first time since 1990 based on more recent and extensive data and the use of sophisticated mapping algorithms. According to the new map, many of us are now gardening in a warmer zone. Here in Ann Arbor, for example, the old map said we were in zone 5b but the new map says we’re in zone 6a — and we’ve definitely seen the truth of that in our gardens.

‘Spic and Span’

In zone 6a Northville, Michigan, Cindy Bullington has seen it, too. She writes, “My glads not only survived without any special care over the past several winters, they became somewhat invasive. I had to substantially thin the gladiolus patch this fall. Love that global warming!”

Sabrina Sheikh of zone 6a Lexington, Kentucky, reports even broader effects in her garden. “I have a number of glads so ordinary they came from the local supermarket,” she writes. “I’ve left them in the ground for about six years now, and they always come back and bloom. I never do anything special for them, and though I have lost a few over the years, most have actually multiplied. Many other plants that are not supposed to survive here have been doing so, too. Tall snapdragons, for example, are now perennials, and when I last looked at my herb garden, I was shocked to see that, although damaged, my parsley and eucalyptus (!!!) were still alive. Climate change? That’s my guess.”

We encourage you to look up your new zone here — but warmer winters aren’t the only thing helping glads return and rebloom.

Reliable Snow Cover

Snow is a great insulator because it holds a lot of air, much like fiberglass insulation or your grandmother’s quilt. In fact, a foot of snow equals about an inch of rain — the rest of the volume is air trapped in the tiny spaces between the flakes. That means reliable snow cover will keep soil from freezing as deeply as it would otherwise, protecting corms that would have frozen to death without it.

For example, Linda Eastman writes from deep in the Adirondacks, “I have seen glads survive in zone 5a Lake Luzerne, New York, for several winters. No cover, special treatment, or anything. Of course there was lots of snow! And here in zone 5a Broadalbin I had a glad live about six years without being dug up, till an extremely cold and snowless winter finally got it.”

In her garden in zone 5b Galva, Illinois, Diane Gibson has seen the insulating power of snow, too: “I sometimes have glads over-winter, but it is usually when we have deep snow all winter and especially if they are planted around something that catches the snow drifts. Always a wonderful surprise.”

Airy Winter Mulch

Although snow is the best insulation, few of us can count on reliable snow cover all winter long. That’s the reason for winter mulches. Unlike common summer mulches such as pine nuggets, winter mulches are meant to capture and hold air, including the air in snow. The air does the insulating, not the mulch itself, so choose materials that won’t mat down easily, such as straw or hay (fluff it up as much as possible when spreading it), oak leaves (which remain stiff and rippled longer than most leaves), evergreen branches, and to a lesser extent shredded bark, shredded leaves, and pine needles.

Winter mulch may also help glads by shedding winter rains and keeping the soil around them drier which is what’s best for all bulbs when they’re dormant.

Linda Galante of zone 6a Livonia, Michigan, understands the value of mulch. Although she plants her glads along the warm south side of her brick house (see Microclimates, below), she also says “I mulch heavily with shredded leaves in November, and pray for snow cover as well.”

‘Fidelio’

In zone 6b New Holland, Pennsylvania, Robert Hohl mulches with 2-3 inches of grass clippings. Though grass mats down and so doesn’t provide much insulation, it’s working for him. “I’m in my 80s now,” he writes, “and with each passing year digging my glads became more of a chore. So three years ago I experimented and left about a quarter of my 200 bulbs in the ground. They all came up. So two years ago I left more than half in, and again they all came up abundantly. So last fall I left them all in.”

Paul Begley of Columbia, South Carolina, reports a historic mulch for glads. “My grandmother lived in the mountains of eastern Kentucky,” he writes, “where it gets quite cold. She never brought her glads in for the winter, but covered them with the ashes and cinders from her coal furnace. The glads not only came through the winter, but over the years spread into a large clump. I know there aren’t many coal furnaces around any more, but maybe something similar would do the trick.”

Deeper Planting

Soil is a great insulator, too, and deep planting is another way to protect corms from freezing. If the cold can’t get down to them, they remain safe and viable.

From zone 6a Lamont, Michigan, a reader who prefers to remain anonymous writes, “I always plant my glads very deep in order to increase the support for the stem and prevent tipping. When I first planted them here, I did nothing to over-winter them because I intended to treat them like annuals. So I was surprised when they returned the next summer. Now ten years later I have come to expect it. Of course it is possible that with our recent mild winters the ground is simply not freezing as deep as I plant my glads — about 10 inches. But so far so good.”

Don’t plant them too deep, though, or your glads may never make it to the surface. Deep planting is safest in sandy soils, since they are lighter and easier for the growing foliage to penetrate.

Sandy Soil and Good Drainage

Sandy soil helps glads in many ways. Water drains through it more quickly, so the dormant corms stay drier in winter and are less prone to rot. Sand particles are larger than clay particles, so there’s more room between them for air, which means sandy soil is a better insulator. And bulbs have an easier time expanding in sandy soils, which means they’re often bigger, healthier, and better able to survive the rigors of winter.

‘Apricot Lustre’

Rhea Dow writes from zone 5b Charlevoix, Michigan, “Yes, glads do survive our winters here. The key is sandy soil and snow cover.”

Slopes also provide good drainage, which may be one of the reasons why David Tomeo of hilly zone 6b Pittsburgh — as well as Linda Eastman in the Adirondacks and Paul Begley’s grandmother in the Appalachians — has had such good success over-wintering glads. (Or is it the compost?) David writes, “Not only do regular glads over-winter in my garden, they spread. Maybe 8-10 years ago when I first planted them, I dug them in fall. Not wanting to be bothered and noticing they were coming back, I quit digging, and they’ve been spreading ever since. I don’t mulch. I do dig-up my beds every 4-5 years to replenish with compost. And any bulb dug up is covered in bulblets.”

Micro-Climates Large and Small

In every hardiness zone there are warmer and colder spots, some large, some small. Urban areas, for example, are usually warmer than more rural areas, as Sherri Ribbey, assistant editor of Garden Gate magazine, recognizes. She writes from zone 5b Des Moines, Iowa, “I’ve had glads come back for maybe five years. I just happened to pick up a bag at a discount store and a few have shown up every year since. I think it helps that I’m smack-dab in the middle of the city and not out in a new suburb or the country where the wind can be pretty fierce and the temperature a little colder. Whatever the reason, it’s nice to have them.”

Every yard has warmer spots, too, where the snow melts first in spring and annual flowers keep blooming long after everything else has been blackened by frost. When you plant glads in these warm micro-climates, you give them a better chance of over-wintering.

In zone 6b Versailles, Kentucky, Sara Hellard writes, “I’ve planted glads in two places by the foundation of our home and they have wintered over quite well with minimal mulch cover.”

Linda Galante of zone 6a Livonia, Michigan, reports similar success: “I have planted all my glads along the south side of my home, and due to the southern exposure and our light colored brick wall I have yet to NOT have glads return. Love, love, love them.”

Jo Sharon of zone 6a Glastonbury, Connecticut, writes, “I’ve had glads survive the winter in both snowy years and dry years. Who knows the reason? My next door neighbor had one survive for years but it was near the heated floor slab of the house. I think the micro-climate there was at least zone 7.”

Susan Krobusek of zone 6a Farmington, NY, also understands the importance of micro-climates — and more intangible factors, too. “I’ve had glads overwinter here in western New York for several years,” she writes. “They don’t all bloom, but they’re still alive. I’m not sure why. One batch was up against the western foundation of the house, so there may have been enough reflected heat to keep them happy there. Another group is in a bed that faces south and east, and has some shelter from the north and west winds, so that could do it. Or it could be that my plants all know how much I love them, and they can’t bear to disappoint me!”

Plenty of Sun

Glads grow best with full sun all day long, and the stronger and healthier any plant is, the more likely it is to make it through the winter. Sunny sites usually don’t freeze as deeply, also, which is another good reason to plant your glads in the sunniest spot you have if you want them to return.

Are Heirlooms Hardier?

‘White Friendship’

Although that’s not a claim we’re willing to make, we will say that any glad that’s survived from the 1960s or before has to be unusually healthy and vigorous, and those qualities may very well help it over-winter more successfully.

Kerry Hoffman in zone 6b Watsontown, Pennsylvania, couldn’t agree more. “I grow cut flowers for market, specializing in heirlooms, and all of my glads are from Old House Gardens,” he writes. “Almost all of the glads I have planted in my cold zone-6b field have returned. ‘Atom’ is astounding in its hardiness, sending up baby shoots as well. I also have white glads that return strongly , and a few violet and apricot colors . I honestly believe that heirloom varieties are tougher, hardier, and less disease-prone than over-hybridized, over-tweaked new varieties.”

“You Just Never Know”

So can anything guarantee that your glads will get through the winter in zone 5, 6, or 7? Probably not, but warmer winters, reliable snow cover, winter mulch, deep planting, sandy soil, good drainage, micro-climates, plenty of sun, and time-tested vigor all seem to be part of the equation. The only way to know for sure if glads will come back in your garden is to give them a try. Most are pretty inexpensive, and experimenting is one of the great pleasures of gardening.

Here’s one last report to encourage you, from Irvin Etienne, Horticulture Display Coordinator at the Indianapolis Museum of Art. He writes, “I had a few varieties of glads in our cutting garden that just started looking crummy, so I decided one fall to leave them in the ground and replace them in the spring. I never ordered new ones, though, and for three years now several have come back big and healthy and blooming the way a glad should. These are in an open area, no protection. I’m not talking 100% survival but pretty darn good. We’ll see what happens this fourth year. You just never know.”

How to Grow Gladiolus

How to Grow Gladiolus Throughout the Season

Growth Habit: Gladiolus have narrow, sword-like leaves and tall flower stalks. The flower stalks can grow 2 to 4 feet tall while only spreading 1 foot wide.

Staking: Gladiolus flower stalks need to be staked, caged or supported so they don’t flop over, or become deformed and curved due to summer storms. Soon after planting, push flower stakes into the ground or add supports around the corm. Do this early so as not to damage the flower. As soon as the flower stalk forms, tie it loosely to a stake with a soft material, or use flower rings to support it. Remove the stakes after the flower is harvested or fades.

Planting gladiolus in groups in the garden or next to tall bushy plants is another way to keep them growing upright without producing crooked flower stalks.

Watering: Keep gladiolus plants well watered with at least 1 inch of water a week. This amount may have to increase during periods of drought or if you’re growing in raised beds.

Fertilizing: Add compost to the soil before planting gladiolus. Add an organic, water-soluble fertilizer when the plants are 10 inches tall, and again when the flowers start to show color.

Trimming & Pruning: Gladiolus are either grown as a cut flower for indoor arrangements, or as an annual flower in the garden. They don’t require trimming or pruning.

The flower stalk is harvested in the morning for flower arrangements when the lower 3 blossoms on the stalks begin to open. Leave at least 4 leaves on the plant to rejuvenate the corms if you plan on saving them for next year.

In the garden, deadhead the flower stalk after the flowers fade. This will also prevent the flowers from setting seed and self sowing throughout your beds. Although these seedlings will eventually get large enough to flower, it will take years and the seedlings can become weedy.

Mulching: To preserve soil moisture, mulch plants once they emerge from the soil with a 2 to 3 inchthick layer of straw or bark mulch. Gladiolus don’t compete well with weeds. If the area where you’d like to plant is weedy, weed before applying the mulch. The mulch should help with weed control as well.

Gladiolus: End of Season Care

Dividing & Transplanting needs: In USDA hardiness zones 6 and colder, gladiolus corms are best dug and stored indoors in the fall. They aren’t hardy enough to reliably survive the winter cold. Here’s how:

  • After the leaves have started to yellow, cut back the foliage to the ground and dig the corms.
  • Let the corms dry in a warm, airy location out of direct sunlight for 3 weeks.
  • Once dry, knock off the soil from the corms and remove and discard the old bottom corm. You may notice small cormlets attached to the new corm. You can remove and discard small ones, but keep the largest ones (about ½ inch diameter) to grow as separate plants next year. It may take 2 to 3 years of growing and saving these corms, but they will eventually become a flowering gladiolus plant.

Cold Climate Storage: Store the corms in mesh bags in a well-ventilated, dark room with temperatures between 35F and 50F.

Warm Climate Overwintering: In USDA hardiness zones 7 and 8, gladiolus corms can be left in the ground and will come back each year. Cut back and compost the tops in late fall. In colder areas of this range, mulch the corms in late November with a 4 to 6 inch thick layer of chopped leaves or straw to provide more winter insulation.

Pests/ Disease: The best way to avoid insects and disease problems on gladiolus is to buy healthy corms that are not soft or crumbly. Discard any damaged or rotting corms that you are storing. If you notice stunted, gnarly growth on one gladiolus plant during the growing season, remove and destroy the plant and corm. It probably has a virus.

The biggest pest of gladiolus is a small insect called thrips. Thrips feed on the flowers and leaves causing characteristic streaking and discoloring on the flowers. Thrips over winter on the corms that you are saving. You can discard corms after one year and buy new corms each year to avoid this program. Or you can treat your corms before storing, by dipping them in boiling water for 2 minutes to kill the thrips. Dry before storing. During the growing season, spray your gladiolus plants at first signs of damage with Neem oil or insecticidal soap to kill them.

Gladiolus

Gladiolus is the largest genus in the Iridaceae family with 255 species. It has been studied by taxonomists and now includes Acidanthera, Homoglossum, Anomalesia, and Oenostachys along with species once included in Antholyza. The geographic range includes Africa, Madagascar, Europe, and the Middle East. Gladiolus has been a treasured flower in many areas of the world. Many of the fancy hybrids that are popular garden plants had their origins in some of the South African species. Telling apart the European species commonly grown is challenging for most of us, especially since seed exchanges use a multitude of different names for what is probably the same species. Angelo Porcelli has written a paper entitled Gladiolus of Southern Italy that helps distinguish between Gladiolus byzantinus (considered by some to be a synonymn of Gladiolus communis), Gladiolus communis, and Gladiolus italicus.

Gladiolus plants are subjected to Thrips, especially the ones that grow and bloom in warm weather.

The standard reference book for the South African Gladiolus species is probably Goldblatt & Manning’s hefty Gladiolus in Southern Africa. Another useful reference is Gladiolus in Tropical Africa.

Many of the winter-growing South African species have delicate-looking, multicolored flowers that bear little resemblance to the large, bold-colored summer-growing hybrids found in garden centers. But many of them are tough plants that can persist in the ground in a mediterranean-climate garden, and a few species (particularly Gladiolus tristis) will spread themselves around the garden by seed. These spreaders probably shouldn’t be grown next to wild land in mediterranean climates.

The name derives from gladius a short sword in Roman times (as in gladiator), and this is the name Pliny (around the first century AD) used in reference to the shape of the leaves of the species he was familiar with. It is said gladiators who survived were showered with gladioli and there is a Dutch saying “death or gladioli” which harks back to this.

Growing from seeds is not difficult for species in this genus. It is said that South African species require temperature under 20 °C to germinate successfully but Bill Richardson found that temperature fluctuation from -2 °C (28 °F) to nearly 20 °C (68 °F) during the day does not have a huge effect on germination. Since there are summer and winter growing species, one must choose the right time for planting. Winter growing species should be planted in the fall. Summer growing species should be sown in the spring, and require somewhat warm temperature to germinate well. Room temperature (25 °C/77 °F) works well. Sow the seeds in a well-drained mix and slightly cover with the mix. The papery wings that surround the seeds do not need to be removed. After sowing, place the pots in a tray with water and allow the medium to soak thoroughly. Above watering can dislodge the seeds and cause them to float to the surface. The seeds are most viable when planted within 1 year, although they can remain viable for longer. Allow a dry summer dormancy for the winter growing species and a dry winter dormancy for the summer growing species. It is probably best to not transplant the seedlings until they have completed their second season of growth.

Information on named species can be found on the wiki pages below or by clicking on the name of the species in the table.

The alternative Gladiolus indices list the same species sorted by color or growth cycle.

Jump to: U A B C D E F G H I K L M N O P Q R S T U V W

Gladiolus species

G. Unknown_Eurasian_Species

G. abbreviatus

G. acuminatus

G. alatus

G. albens
G. anatolicus G. angustus G. antholyzoides G. appendiculatus G. aquamontanus
G. arcuatus G. atroviolaceus G. aurantiacus G. aureus G. bilineatus
G. blandus G. blommesteinii G. bonaspei G. brevifolius G. brevitubus
G. buckerveldii G. bullatus G. byzantinus G. caeruleus G. cardinalis
G. carinatus G. carmineus G. carneus G. caryophyllaceus G. cataractarum
G. ceresianus G. citrinus G. communis G. comptonii G. crassifolius
G. crispulatus G. cunonius G. cylindraceus G. dalenii G. debilis
G. delpierrei G. densiflorus G. deserticola G. dolichosiphon G. dolomiticus
G. ecklonii G. edulis G. equitans G. exiguus G. exilis
G. ferrugineus G. flanaganii G. floribundus G. fourcadei G. geardii
G. gracilis G. grandiflorus G. griseus G. gueinzii G. guthriei
G. hirsutus G. hollandii G. huttonii G. hyalinus G. illyricus
G. imbricatus G. inandensis G. inflatus G. inflexus G. insolens
G. involutus G. italicus G. kamiesbergensis G. karooicus G. leptosiphon
G. liliaceus G. longicollis G. loteniensis G. macneilii G. maculatus
G. magnificus G. marlothii G. martleyi G. meliusculus G. meridionalis
G. microcarpus G. miniatus G. monticola G. mortonius G. mostertiae
G. murielae G. mutabilis G. natalensis G. nigromontanus G. ochroleucus
G. odoratus G. oppositiflorus G. orchidiflorus G. ornatus G. overbergensis
G. paludosus G. palustris G. papilio G. pappei G. pardalinus
G. parvulus G. patersoniae G. permeabilis G. phoenix G. pillansii
G. primulinus G. priorii G. pritzelii G. psittacinus G. pubigerus
G. pulcherrimus G. punctulatus G. quadrangularis G. quadrangulus G. recurvus
G. reginae G. rehmannii G. rhodanthus G. robertsoniae G. robustus
G. rogersii G. roseovenosus G. rudis G. rufomarginatus G. saccatus
G. salmoneus G. salteri G. saundersii G. saxatilis G. scabridus
G. scullyi G. sekukuniensis G. sericeovillosus G. serpenticola G. speciosus
G. splendens G. stefaniae G. stellatus G. stokoei G. subcaeruleus
G. sufflavus G. symonsii G. taubertianus G. teretifolius G. trichonemifolius
G. triphyllus G. tristis G. undulatus G. uysiae G. vaginatus
G. vandermerwei G. venustus G. vernus G. vinosomaculatus G. violaceolineatus
G. virescens G. virgatus G. viridiflorus G. watermeyeri G. watsonioides
G. watsonius G. wilsonii G. woodii

Southern African Gladiolus A-B – Southern African Gladiolus Ca – Southern African Gladiolus Ce-E – Southern African Gladiolus F-H – Southern African Gladiolus I-Me – Southern African Gladiolus Mi-Pa – Southern African Gladiolus Pe-R – Southern African Gladiolus S-T – Southern African Gladiolus U-Z – Gladiolus Hybrids – Miscellaneous Gladiolus

Return to the PBS wiki Photographs And Information page

How to plant and grow gladioli

Gladiolus are, in many ways, like the summer tulip and are no more difficult to grow. They make wonderful cut flowers and growing gladioli is easy. Like all good garden bulbs, if you get them growing in the ground they will flower.

Planting

Soil and Site

On rich but well-drained soils, you can plant them straight out in the garden. On my heavy clay – particularly in a wet spring – I tend to plant my glads in pots and put them out in a clump already growing.

Spacing

Plant the corms 10cm (4in) apart and 10-15cm (4-6in) deep. Secured deep in the ground, you are less likely to need a stake.

In the garden

Gladioli need plenty of water to flower well, so if you can, dig a trench and pile in well-rotted manure at the base before planting. This will help feed the bulbs and will also retain water to ensure a more regular supply. If you have bought quite a few, don’t plant them all at once. Plant fifteen corms every couple of weeks from early May to July to give a succession of flowers through the summer and autumn.

For containers

Plant five corms in a 15cm (6in) pot at 20cm (8in) deep, so a bit more closely packed than recommended above. Put them somewhere bright and cold, but frost-free, and water. Wait for them to shoot and plant them out in the garden from May onwards, by which time you’ll have well established plants. They will need staking. To avoid piercing the corms, canes are safest poked in before you plant the bulbs.

On well-drained, poorer soil, extra watering will be required. Apply a high potash feed, like comfrey pellets or tomato fertiliser every two weeks as soon as the flower spikes are 15cm (6in) high and until at least three weeks after flowering. This is essential on poor soils as flowering can diminish in successive seasons. Gladioli will flower three months after planting.

Aftercare

It’s always said you need to lift your gladioli – that, like dahlias, they’ll be frosted if left in the ground. It’s my fourth year of growing them at Perch Hill and I’ve never lifted them. I mulch them deeply with 6-7cm (2.5in) of mushroom compost to give them an insulating duvet over their heads in late autumn. You should be safe with this in the south of England and the western fringes of the British Isles, but in colder counties, grow them in a sheltered spot and lift them for the winter when the leaves turn yellow-brown. Lift them and snap the corms from the stems. Dust with sulphur and dry them out for a couple of weeks. Then snap the new corms from the old, discarding the old. The new must be kept dry and cold (but frost-free) until they are replanted.

You can dig and divide the clumps every few years to select the best corms for replanting. Without this, the new cormlets forming will invade the space of the original corm and the nutrients will have to be shared. The danger of this is the creation of lots of foliage and no flower spikes.

Cut Flowers

Remove the bottom leaves, I prefer to leave the spike tip as this is part of the plants appeal but removing it will encourage more flowers below.

Leave a Reply

Your email address will not be published. Required fields are marked *