The Old House Gardens Guide
For Preserving and Enjoying Heirloom Bulbs
We want our customers to have great success with all of our bulbs, so we do our best to provide complete, accurate information on planting and care. Here’s the “Heirloom How-To” we send with our bulbs. More is included (especially for our fall-planted bulbs) on the “bag-tags” stapled to each individual bag.
For SPRING-Planted Bulbs (or click here for Fall-Planted Bulbs)
Though we hand-inspect every bulb/corm/rhizome/tuber we ship, please unpack yours right now and count and re-check them. Small blemishes and bits of mold rarely affect performance. But if bulbs feel mushy, or anything else seems amiss, please email or call us immediately so we can remedy the problem (or set your mind at ease). Our aim is always to deliver absolutely fantastic bulbs!
Don’t Plant Outside Too Early!!!
These mostly sub-tropical bulbs often fail if planted before the soil is reliably warm. Planting too late is better than planting too early outdoors.
Plant Inside Now — Or Store Carefully
If it’s too cool to plant them outside just yet, please be careful with these treasures because they are often more vulnerable in storage than our fall-planted bulbs. If you don’t start them indoors — or follow our instructions here for storing them temporarily — YOU COULD LOSE THEM. Most of these bulbs can be stored in the bags they arrived in, leaving the tops loosely open. Temperatures should be as noted below, but close is usually good enough.
No, You Don’t Have To Dig Them Up In The Fall!
Most of us enjoy a lot of plants in our gardens that we rarely keep through the winter — impatiens, for example. So don’t feel you have to store our tender bulbs. Just ENJOY them, and compost them when they finally freeze. Even if they’re rare, you need not feel guilty. By simply buying them you’re keeping our growers growing them, and that’s preservation, too! Of course if you decide you want to store them, this guide offers easy how-to.
If what you’ve been doing has worked well, keep doing it — even if you read something different here. Climate, soils, and so on vary so much that our best advice may not be right for your bit of Eden.
For Local Advice
Local experts can often tell you more about gardening in your area than we can (though unfortunately we’ve also found that many experts have very little experience with bulbs or heirloom plants). One great resource is your county Cooperative Extension Office or Extension Agent. For the phone number in your county
, go to http://www.csrees.usda.gov/Extension/index.html
and click on your state and then county. Other great resources for local advice include locally-owned garden centers, botanical gardens, universities, garden club members, and friends, neighbors, and relatives who garden, especially older ones who may be more familiar with heirloom varieties.
Questions? Concerns? Disappointments? Suggestions?
Call or email us, please! We want to hear from you. We love our customers and want you to have great success with all of our bulbs.
Like most cannas, ‘Ehemanii’ is easy to grow. All it needs is plenty of sunshine, heat, and water. Unfortunately, unlike most cannas, it doesn’t store well as a dormant rhizome, which is one reason it’s rarely offered today — and why we ship freshly-dug rhizomes in April. Please give yours immediate attention when it arrives or you may lose it.
The weather in April isn’t warm enought to plant ‘Ehemanii’ outside in most places, so you’ll probably need to start it INDOORS in a pot. A clay pot is ideal. Choose one that’s a bit snug because excess empty soil can sour and lead to rot. Plant a couple of inches deep, as deep as it was at our Texas grower’s — look for where the stalk changes from green to white due to being underground.
Put the pot in a WARM spot with as much sun as possible. Bottom heat is helpful, and although a plastic heat mat is the safest way to provide this, many gardeners improvise. Keep soil damp but not soggy until new growth appears. Repot as needed, and don’t plant outside till all danger of frost is past, the soil has warmed up, and nightly lows are reliably above 55° F.
Outside, plant in full sun, 24-36” apart. (‘Ehemanii’ gets big!) Well-drained, fertile soil is ideal, but ‘Ehemanii’ is vigorous and adaptable. Growing it in a large pot — on a sunny terrace or deck, for example — can also work well.
Like all cannas, ‘Ehemanii’ is a very thirsty plant (once it gets going again). It will thrive, grow taller, and bloom more when watered regularly. In fact, when it’s in active growth it’s hard to water it too much. Thoroughly soak the area at the base of the stalks, where the rhizomes are multiplying. A sprinkling system or sprinkler will rarely provide enough water.
Fertilizing is a big help, too, because all cannas are heavy feeders. Give it some rose or tomato fertilizer (not too high in nitrogen) every 2-4 weeks, or use a foliar fertilizer (Miracle-Gro, etc.). Compost is a great help, too.
Pluck off spent flowers to enhance its beauty. To encourage more bloom, cut off flower clusters before seed-pods form.
WINTER CARE — In zones 7 and colder
, if you want to save your ‘Ehemanii’ for the following year you’ll need to dig it in the fall and either (a) store it as dormant rhizomes or (b) keep it growing indoors all winter.
To store as dormant rhizomes, wait a week or so after the foliage is “blackened” by frost, to allow the rhizomes to harden and fully mature. The soil will generally protect them from freezing. Then cut the stalks off a few inches above ground level. You’ll find that the original rhizome you planted has increased into a much larger clump, so be careful when digging it up — start a foot or so away from the stalks. Wash off all soil, cut the stalks down as short as possible, and allow it to dry thoroughly in a cool, dry place for a couple of days. If necessary you can break it into smaller chunks now, but we recommend waiting until spring to do most dividing. Allow any wounds to callus over by air-drying for a couple of days, after dusting them with a fungicide such as garden sulfur if you have it. Store in covered plastic storage boxes or plastic garbage bags inside cardboard boxes in a cool, dry, dark place, ideally at 40-45° F. Check every now and then. Allow excess moisture to escape (look for condensation) or sprinkle a little water on rhizomes if they seem to be shriveling. You can replant the entire clump in late spring, but if you want to divide it, wait until you’re ready to replant and then break it up by hand or cut it with a sturdy knife. Be sure each division includes a stalk or two. Allow the wounds to dry and callus over for a day or two, after dusting them with a fungicide such as garden sulfur if you have it. Plant outside when all danger of frost is past, the soil has warmed up, and nightly lows are reliably averaging 55° F.
To keep it growing indoors — which is usually a safer bet than storing it dormant — when a killing frost threatens, cut the stalks down to 2-3 feet. Dig and divide into chunks with 1-3 stalks each, if possible dust the wounds with garden sulfur or another fungicide, and pot it up immediately, taking care to preserve as many feeder roots as possible. Set in a warm, sunny window, ideally with a bit of bottom heat. Its growth will slow in winter, so reduce watering and do not fertilize. Your goal is just to keep it alive and growing. In late spring when all danger of frost is past, the soil has warmed up, and nightly lows are reliably averaging 55° F, replant it outside for another summer of amazing beauty.
In zones 8-11 (with lows to +10° F), ‘Ehemanii’ can be left in the ground all winter. Leave the stalks intact and mulch with 6-12 inches of leaves, straw, etc. Thin clumps every few years for best performance.
“No crinum has ever died,” says Bill Welch, author of The Southern Heirloom Garden, and he’s only half-joking. Crinums are incredibly tough and adaptable, growing and blooming just about anywhere in zones 7-10, but here’s how to get the best out of your C. x herbertii.
Choose a warm spot with well-drained to average soil, plenty of sun, and — in hotter areas — a bit of afternoon shade. Space 12-24 inches apart or more, remembering that crinums have long, exuberant foliage, they don’t like to be disturbed, and in time they’ll develop into ever-bigger clumps. Plant so the neck of the bulb is just below the soil surface. Water well.
Crinums have fleshy, permanent roots and are typically slow to re-establish after being transplanted. Expect NO blooms the first summer as the bulb puts its energy into developing roots, leaves, and buds (inside the bulb) for next year’s bloom. Good care the first year is especially important. Keep the soil lightly moist but not soggy (crinums can survive in very dry soils but do much better with regular watering), fertilize lightly, and avoid trimming the leaves as much as possible.
— In the fall, especially the first year, the leaves may yellow and die back — or get frosted off — and the plant may go dormant
for a few months. Refrain from watering until new growth appears in the spring. In warmer zones or when the plant is fully established, leaves may not yellow until spring, or not at all. Feel free to neaten them a bit if they become ratty, but remember that the more the bulb can photosynthesize, the more it will grow, bloom, and multiply.
— Where they’re not hardy, crinums can be grown in pots. Choose a clay pot that’s not too big
. Spread the roots and set so the bulb neck is just above the surface of the potting soil. Set in full sun and keep soil lightly moist but never soggy. When frost threatens
in fall, bring inside to grow in a sunny window
. In late spring, trim leaves and move outside. You can also store potted crinums in the basement over the winter. Learn more here
from two New England customers.
CAUTION! In warm climates, Crocosmia multiply vigorously and can easily become INVASIVE. Do NOT grow near streams, lakes, etc. Do NOT compost corms, cormlets, plants, or the soil they’ve grown in. Instead, dispose of by bagging in plastic or burning.
There’s no need to panic, though. In a well chosen spot, with reasonable care, crocosmia can bring you decades of pleasure, as they have for generations of gardeners.
For best results, well-drained soil is crucial. Avoid or improve clay soil, or grow in raised beds or pots with a fast-draining soil mix. Crocosmia prefer full sun to part-shade in the South and full sun in the North.
Plant corms after the last-frost date in spring. If necessary, store till then in open bags in a cool, dim, dry place. Plant with the pointed end up, 2-3” deep and about 8-10” apart. Water well.
Foliage usually emerges within a couple of weeks. After bloom, allow the leaves to continue growing to feed the bulbs for increase and next year’s flowers. Remove only after they yellow into dormancy in the fall.
— Where they’re not winter-hardy, crocosmia can be stored as easily as glads. Dig them after first frost and immediately cut the stalks off as close to the corms as possible. Air dry for 2-3 weeks at 60-70° F. Some experts recommend dusting corms with an insecticide-fungicide before storing, but many gardeners skip this. Store loose or in mesh bags or even old nylon stockings in a cool, dry place with good air circulation, ideally at 35-45° F. Please remember: to prevent them from becoming invasive, do NOT compost
corms, cormlets, plants, or soil. Bag in plastic or burn instead.
Don’t be surprised if your dahlia tubers all look different. Some are long, some round; the ones from the Netherlands are often homely clusters of small tubers while the ones from Oregon are single, often larger tubers. Both will produce plants of equal quality, equally fast. The difference is simply due to the way the tubers are produced at our growers: small-scale, traditional growing in Oregon vs. modern “pot-root” production in Holland.
Some of the tubers in the pot-root clusters may have “broken necks” and be dangling from the crown by just a few threads. You can leave them but since they probably won’t grow, you may want to break or cut them off. You only need one good, well-connected tuber in each cluster to make a full-size plant.
Don’t plant outside too early! Wait till after all danger of frost is past — when you’d plant tomatoes or later. That may mean you have to store your tubers for a month or more. Open the bags and leave them loose at the top so air can circulate. Store in a cool, dim-to-dark place. 40-45° F is ideal, but warmer — even cool room-temperature — works, too.
If your tubers sprout while waiting to be planted, it’s not a big deal. You could pot them up and start them indoors, but it’s not essential. If a sprout breaks off, don’t panic. Usually several more will emerge at the base of the broken one.
For a longer season of bloom, you can start tubers inside 4-6 weeks early and transplant them outside when it warms up, which is what we do. Be careful not to over-water pots, especially at first. Give strong sun, or set outside on warm days.
Dahlias thrive in light, fertile, well-drained soil. If your soil is heavy (clay), add organic material or plant in raised beds. Full sun is best, but eight hours will do. Dahlias do NOT like extreme heat (they’re native to cool mountain plateaus in Mexico), so avoid hot spots such as near south or west walls, and if you garden in the Deep South or other hot areas, see our special tips below.
Space your dahlias 18-24 inches apart. Dig a hole a foot deep and wide; enrich the soil and return some to the hole. Pound a sturdy stake into the ground near the center of the hole so that 3-7 feet of it remain above ground level (depending on the ultimate height of the dahlia). In front of this, lay the tuber horizontally with the eye, if visible, pointing up — or set the entire pot-root cluster with the stem facing up — about 6 inches below ground level. Cover with 2-3 inches of soil. If your soil is moist, DON’T WATER tubers until they sprout. In soggy soil, un-sprouted tubers are prone to rot. If your soil is dry or the weather is hot, you will need to water, but don’t overdo it — till sprouts emerge.
As shoots grow, gradually add soil till the hole is filled. For bushier plants, “top” them after they get three sets of leaves by pinching or cutting out the center shoot. If slugs or snails are a big problem in your area, consider using bait.
Water regularly during the growing season, and fertilize lightly every 3-4 weeks until early fall. Don’t over-feed! AVOID HIGH NITROGEN FERTILIZERS such as lawn fertilizer. Use balanced rose, tomato, or general garden fertilizer instead. Hand-weed; avoid ALL herbicides. Dead-head by cutting spent blooms to encourage more vigorous flowering — or simply pick lots of bouquets! Dahlias like cool conditions (they long for the cool mountain plateaus of Mexico), so growth and flowering peak as temperatures cool in late summer and early fall.
is a lot like staking tomatoes, except dahlias are easier. We find that double strands of garden twine work well, and if it’s green it all but disappears. Tying individual stalks or at most a few at a time to the stake usually looks much better than tying a big bundle all together. As the stalks continue to grow, you’ll have to tie them again higher up. Some growers use wire-hoop “tomato towers” along with the stakes and let the dahlias pretty much support themselves within the towers. For more guidance, see dahlias.net/dahwebpg/Support/Support.htm
IN THE SOUTH AND WARM WEST
— To grow and bloom well, most dahlias need cool night temperatures — as in the Mexican highlands where they’re native — which is why we recommend them only for zones 4-7b in most of the country and 4-9b on the West Coast where summers are cooler. But some dahlias can handle warm nights better than most, and we recommend these varieties — noted as “heat-tolerant” in their descriptions and “heat-ok” in our dahlia chart
— through zone 8b in most of the country and 10b on the West Coast.
According to our friend John Kreiner of the Dahlia Society of Georgia, there are two keys to getting dahlias to thrive where summers are hot: (1) mulch them, and (2) choose heat-tolerant varieties. To learn more from John and our dahlia-loving customers in zones 8 and 9, go to oldhousegardens.com/DahliasForHotNights
In zones 8-11 you can leave your dahlias in the ground all winter. Add 4-6 inches of mulch directly over the tubers. Most growers cut the stalks down at some point, and John recommends capping each with a bit of tin foil and a rubber band so water doesn’t collect in them and rot the crown and next year’s sprouts. Dig and divide tubers every 2-3 years.
WINTER CARE — In zones 7 and colder, if you want to save tubers for re-planting the next spring, wait a week or so after the foliage has been “blackened” by frost, to allow tubers to harden and fully mature. The soil will generally protect them from freezing. Then cut the stalks off a few inches above ground level. You’ll find that the tubers you planted in early summer will have increased into much larger clumps, so be careful when digging — start at least a foot away from the stalks. Tag each clump with its name, wash off all soil, and allow it to dry upside down in a cool, dry place for a day or two, no more.
Divide the clumps with a sturdy knife in fall or spring. Be sure a piece of the “crown” — the thickened area where the stem meets the tuber — remains attached to every clump, because the eyes (often more visible in fall) are located there. You may want to dust cuts with a fungicide such as garden sulfur. At the least allow cuts to air dry for a full day before storage.
Store in plastic grocery bags, in plastic garbage bags inside boxes, or in covered plastic storage boxes to help keep the tubers from dehydrating. Pack in coarse vermiculite, peat moss, wood-shavings, or something similar. Store in a cool, dry, dark place, ideally at 40-45° F. Check every now and then. Allow excess moisture to escape (look for condensation) or sprinkle some water on tubers if they seem to be shriveling.
Or here’s an easy way recommended by Marian and Bernard Mandella and Richard Peters in the Bulletin of the American Dahlia Society, September 2001. “Tear off a sheet of plastic wrap 20 or more inches long and lay it flat on a level surface. Place a [divided, dusted, and dried] tuber on one end and roll the plastic wrap over one complete turn. Lay another alongside and roll again. Be certain that no tuber is touching another. . . . You may wrap up to five tubers or so per package, but in the last 5-7 inches, fold over the side portions of the plastic wrap and continue to roll to completion. Fasten with a piece of masking tape that is labeled with the cultivar’s name. . . . There is essentially no loss from shriveling or drying.”
Some of our customers who grow dahlias in pots just bring them inside and let them dry out and over-winter right in their pots. Others grow them in 5-gallon or even 1-gallon black plastic nursery pots that they bury in the garden and then dig up and store in the basement through winter. You may want to experiment with these extra-easy storage methods, too!
Plant these bare-root perennials as soon as possible in the spring. They’re eager to grow, can take light frost, and need water and sunlight to stay healthy. If necessary, store in a plastic bag in the refrigerator for a few days or “heel in” briefly in moist sand or soil in a shady spot.
Daylilies like lots of sun but most bloom well in light shade, too, and often prefer it in the South. Loamy, well-drained soil suits them best, but they’re adaptable and should do fine in any soil that’s not too wet or dry.
Plant 18-24 inches apart (to leave growing room for future years) with the crown (where the foliage meets the roots) no more than one inch below the soil surface. Dig a hole big enough to fit the roots comfortably, mound soil in the center, set the plant on top, and spread the roots out down the sides of the mound. Fill in and firm soil around roots, making sure the crown ends up no more than one inch deep. Water well.
Water regularly, especially the first year and from spring till flowering in future years. First-year plants usually bloom sparsely — if at all — concentrating instead on developing a strong root system. Deadhead (remove) spent blooms daily for a neater look and, to increase bloom the following year, remove any seedpods that may form.
After bloom, normal senescence (aging) may cause foliage to subside, yellow, or turn brown at the tips. If this bothers you, feel free to trim it a bit or even cut the foliage to the ground completely — though not the first year! With good care, fresh new foliage will emerge.
Daylilies are hardy perennials and winter protection is rarely needed. In spring, remove dead foliage, fertilize if indicated by a soil test, and resume watering.
For more information, including tips on the few pests and diseases that occasionally trouble daylilies, see the “Frequently Asked Questions
” section of the excellent American Hemerocallis Society website.
For zone-6 hardy Carolina Primrose and Boone, see additional information on our bag-tags.
For fall-planted, zone-6 hardy Byzantine glads
, see special planting and care info here
For all other glads — Plant after danger of frost is past — when you’d plant tomatoes. Glads planted in cold soils may rot. Open the bags and store till then in a cool, dim, dry place. 45-55° F is ideal, but close will do.
For a succession of bloom, follow old-time advice and soak some corms before planting to speed them into growth and bloom. Or plant a few every week or two till the end of early summer (for example, late June in zone 5). Don’t wait too late, though, because some heirlooms need a longer season than many modern glads to bloom.
Pick a sunny site. Glads are easy and adaptable, but loose, fertile, well-drained soil with a pH of 6.5 to 6.8 is ideal for them. Avoid heavy soils that stay wet. Plant 4-6 inches apart and 2-6 inches deep, the side with the round indentation in the middle facing down. Shallow planting gives the corms warmer soil to spur growth but it may lead to a need for staking. To help avoid this, mound soil 2-3 inches around the base of the stalk later, before bloom.
Water once, but then unless it’s very dry, wait till growth emerges before beginning to water regularly and deeply enough to reach the corm. Expert glad-growers often recommend mulching to maintain more even moisture. Fertilize when growth begins and again after cutting flowers, ideally with a liquid fertilizer. Don’t overdo it, though. Too little is better than too much.
Glads do well in pots, too. When they bloom you can set them in the border where needed á la Gertrude Jekyll.
are one of the few pests that bother glads. They’re almost invisible but they can be devastating. To learn more, click here
— In zones 8 and warmer (lows to 10° F), glads can stay in the ground year round. They often survive winters in zones 7, 6, and even 5, too, according to many of our customers. Learn more at our Surprisingly Hardy Glads page
Otherwise, glads are one of the easiest bulbs to store (if you want to). Dig 5-6 weeks after flowering or at killing frost. Cut stalk off as close to the corm as possible. Experts often recommend a 5-minute fungicide dip, or you can dust them with an insecticide-fungicide, or do nothing. Air dry for a few weeks. Store loose or in mesh bags in a cool, dry place with good air circulation, ideally at 35-45° F. In spring, break off the old, shriveled corm at the base of each new one.
bigger than a pea may bloom the next year, and smaller ones in two. Plant cormlets 1-2 inches deep and 1-2 inches apart, depending on size. Immediately before planting, nick, gently crack, or dissolve hard outer coats by soaking in bleach for a few hours. Learn more.
SMALL IS BEAUTIFUL
— Small-flowered and species glads can be even easier to grow. To learn more, read Scott’s 2006 article for the Brooklyn Botanic Garden, “Glads for Glad-Haters.”
Unlike most sources, we ship our iris as bare-root plants in the spring
. (See an example here.
) Plant them right away. They’re freshly dug, can take light frost, and to bloom their first summer they must get growing again ASAP. If necessary, store in the fridge for 2-3 days or “heel in” briefly in moist sand or soil.
Iris like lots of sun. Give them half a day, at least, or more for increased bloom and better health. Good drainage is essential, too, so plant in sandy to average soil. Avoid or improve heavy (clay) soil or plant on a slope or in raised beds.
Space 10-18 inches apart. Iris grow/expand outward from the leaf end of the rhizome (bulb), so keep this in mind when arranging and planting them.
Don’t plant too deep! Leave the top of the rhizome exposed. Dig a hole, mound soil in the center, set plant on top, and spread roots down the sides of the mound. Fill in and firm soil, making sure that the top of the rhizome remains exposed (or barely covered in extremely hot climates). Water well.
Though iris are drought-tolerant and will rot in soil that’s too wet, they’ll need regular moisture the first few months after planting as they reestablish themselves. So water them, but not too much. Let your green thumb be your guide.
After flowering, cut bloom-stalks to the ground. Weed carefully to avoid damaging shallow feeder-roots. For best bloom and health, trim or remove dead or disfigured leaves (but not healthy green ones!), especially in late fall and early spring, so air can circulate freely and sunshine can warm the rhizomes.
After a few years of vigorous growth, your iris may get so crowded that their bloom and health begin to suffer. To thin or divide them, wait 2-4 weeks after bloom and then either open up the clump by removing the oldest rhizomes from the center, or dig it all, replant the best new rhizomes, and give away or destroy (don’t compost) the others.
Iris have relatively few pests or diseases
that trouble them. For helpful advice on the most common ones — iris borer
(which is only a problem east of the Rockies), leaf spot, and root rot
— see the excellent Iris Garden website sponsored by the iris societies of New England.
Rain lily bulbs are so small, it’s best to plant them as soon as possible. But you have to wait till all danger of frost is past — when the soil warms up and night temperatures remain near 60° F. You can check the average low for any zip code and any day of the year at weather.com and similar sites. If that means you have to store them, leave the plastic bags loosely open at the top so air can circulate a bit and set in a cool, dim place. 50-60° F is ideal, but close will do. Keep an eye on them to make sure they don’t dry out completely.
White rain lilies are hardy in zones 7 and warmer (lows to 0°F), pink in zones 8 and warmer (to 10°). To bloom well, both need hot summers. Plant outside 1-2 inches deep and 2-3 inches apart. Though they prefer full sun and moist loam, they are very easy to grow (“absurdly easy and prolific,” Scott Ogden writes in Garden Bulbs for the South) in a wide range of conditions, even damp clay. In their native Argentina the white ones actually grow in marshland! Protect them from greedy tree roots and keep them watered in dry spells and they will reward you with even better growth.
In colder areas, they make interesting plants for pots (especially the pink ones). Plant about 1 inch deep and crowded close together — they reputedly bloom best when pot-bound — in "cactus mix" or another quick-draining potting soil. Water well. To stimulate bloom, many authorities recommend setting them in a saucer of water once well established. Heat is important, too!
— In areas where they’re not winter-hardy, bring inside at frost. Dry and store right in the pot or in dry peat moss, coarse vermiculite, etc., ideally at 50-60° F. Replant — or begin to water again — in the spring after last frost, fertilizing regularly to promote rebloom.
St. Joseph’s Lily
Care for this great old amaryllis the way you would any other amaryllis. It’s just a lot hardier! You can grow it outdoors in zones 7 (possibly 6b) and warmer, or in a pot anywhere.
Unlike modern amaryllis, heirloom amaryllis — with their long, fleshy, permanent roots — don’t like to be moved and often take a long time to re-establish themselves. So if yours doesn’t bloom this year, please don’t be too disappointed. All of our bulbs are blooming-size, and these glorious beauties are well worth waiting for!
To grow it outside, choose a spot in full sun if you’re in the northern parts of its range, or in light shade further south. Fertile, well-drained soil is best, but St. Joseph’s lily can thrive in heavy clay, too. Outside, plant so that the neck of the bulb is just barely buried. Water sparingly till the foliage resumes growth — which can take distressingly long — then water well and fertilize as long as it is actively growing. Stop when the leaves begin to yellow and the bulb goes into dormancy in the fall. (You may actually find the foliage stays evergreen for you.) In the northern parts of its range — zone 7 — we recommend deep, light winter mulch (straw, etc.) for winter protection, just in case. You don’t want to lose this bulb to an unusually harsh winter!
To grow in a pot, choose a clay pot that’s just a bit bigger than the bulb and use a fast-draining potting soil. Plant so that the top third of the bulb is exposed. Water sparingly till the foliage resumes growth — which, again, can take distressingly long — then water and fertilize regularly. When outdoor temperatures warm up, put it in a sunny spot outside or plunge it, pot and all, into the garden. The better it grows through the summer, the better it will bloom next year. In fall, bring indoors for the winter. At this point, most experts recommend that you gradually withhold water to encourage dormancy and then leave the pot completely dry for 2-3 months. When you can’t wait any longer, or you see green growth emerging again in spring, gently remove the top layer of soil (without injuring any roots), replace with fresh soil, and resume watering and fertilizing. On the other hand, some experts report success re-blooming St. Joseph’s lily by keeping it growing in pots throughout the year, without a dormant period. They do recommend giving it some fall chilling, though — but not freezing. You may want to experiment (and let us know!).
Tuberoses are easy to bloom if you start with our big bulbs and give them a long hot summer. To store till planting, just open the bags and set in a cool, dim, dry spot. 55-70° F is ideal, but close will do.
In the NORTH, we recommend growing them in pots. You can start them inside 4-6 weeks before the last frost date. Set them close together and so their tips are barely covered with soil. Water and put them in a warm spot, maybe with a little bottom heat (a greenhouse heating-mat works great). Keep moist but not soggy. Once leaves emerge — which can take up to a month! — water and fertilize regularly. When nights stay in the 60s reliably, move the pot outside to a spot that’s as hot and sunny as possible — but where you can keep them well-watered. Continue to water often — probably daily — and fertilize regularly. Once they get growing, tuberoses need FULL SUN, CONSTANTLY MOIST SOIL and PLENTY OF NUTRITION to do their best. If blooms don’t appear by the time the weather cools in latest summer, bring the pot indoors to a sunny window and enjoy the blooms there.
In the SOUTH, you can bloom them successfully in the ground, where singles tend to do better and bloom earlier. Plant bulbs in early summer, in a hot, sunny spot with well-drained soil, 4-8 inches apart with about 2 inches of soil over their tips. Water once but unless it’s very dry wait till leaves emerge before watering again. Then keep soil moist and fertilize regularly. Tuberoses need LOTS OF SUN, CONSTANTLY MOIST SOIL, and PLENTY OF NUTRITION to do their best.
— In zones 9 and warmer (lows to 20° F), tuberoses can be left in the ground year-round.
Elsewhere keep them growing as long as you can in the fall but eventually reduce watering till the foliage dries up or there’s a hard frost. Dig and store as glads (see above; no need for a fungicide dip), or dry and store them right in their pot.
In the spring, dump out the rhizomes. Each will have produced a cluster of daughter bulbs. Experts say that once a tuberose bulb blooms, it won’t bloom again, but any of the daughter bulbs that have reached the size of your thumb or so will bloom, and often smaller ones will, too. So add new soil to your pot and either replant the whole clustered bulb-clump or break off the largest daughter bulbs and replant only them.
An even simpler way that works well for us is to just leave the rhizomes right in their pot the second year and water and feed them heavily through the summer. However, by the third year they will have grown too crowded and you must repot. No matter what you do, regular fertilizing is always important to assure re-bloom.
Learning From You
We want to know more about growing bulbs successfully — all over our wonderfully diverse country. Our own experience feels limited (so much gardening, so little time!), and though we’ve learned a lot from books and articles, we’ve also found that not all published advice can be relied on.
So we’d love to hear about your methods, tips, hunches, experiments, discoveries, resources, and whatever else — especially if you garden in conditions different from our mostly zone-6a, sandy-loam, Midwestern gardens. Please write, call, email, or Facebook us!