Rhizomes & Tubers & Corms! Oh My!

Technically speaking, I can add the true bulbs to this little ditty, but it just Cool and refreshing caladiums. Image licensed through ©iStockphoto.com/Richard Hoffkins Design, photographer. wouldn't have sounded quite right. What we call "Summer Bulbs" is the subject of this little piece. Point is made that many of these "bulbs" aren't bulbs at all, but who really cares when the results are the same: flowers, flowers, and more flowers! All the plants discussed here are tender; that is, they don't take to freezing temperatures. Gardeners should try a few, and learn to over winter them. It's the way to save money, and with the cost of everything, and I mean everything going up, who doesn't want to save a few bucks? Let's take it from the time we wake these hot-blooded ladies up until we put them back to bed to sleep for the winter!

Let's get crackin' then...

Tuberous Begonias

If it's late February or into March in the Southern Great Lakes Region, then it's time to start waking up the tuberous begonias for the annual summer block party.

Tuberous begonias come in a wide array of colors and shapes. They can be upright or cascading, and they make wonderful subjects for shade beds, hanging baskets, and containers. Every color shade but blue is represented, and a rare few are scented, too. All add wonderful brightness to a shady nook or porch, and can take the heat, so to speak. They won't balk during the hottest part of the summer.

Tuberous begonias are, well, tuberous rooted plants. They actually look like little saucers. One end is rounded, the other is a cuplike depression with little potato-like eyes or bumps imbedded in it. The tuber is planted rounded or curved side down, the cup or the eye-side up. (Don't feel that I am talking down to you. From time-to-time, some reasonably intelligent people have been known to plant things in the wrong way: You are reading from one of them right now)! Anyway, I use a sterile, non-soil based plant medium, sterilized plastic pots, the 4-inch or larger sizes that I have saved from my prior purchase. I clean them and then sterilize them in a solution of 2 Tbsp. household bleach to the gallon, rinse them, and then allow them to dry.

When planting these, just pop them on top of the moistened-medium filled pots and then cover them with more of the planting medium, no more than 1/2 inch on top. Put them into a sunny area on a tray, and cover with plastic wrap until they have started to sprout. Fertilize them with a liquid soluble organic fertilizer once they have several sets of leaves, about every week to ten days with a half strength solution of fish emulsion or kelp. Don't allow them to dry out, and don't get fertilizer on their leaves, to prevent spotting. Before whipping them out of the house and into the garden, harden them off in late May for a week or so before planting them.

Be careful when transplanting, as these plants have brittle stems and you don't want to sacrifice what you have accomplished! Be careful not to set the plants any deeper than they grew in their containers. Continue to fertilize them, keep them deadheaded, and they will go on throughout the warm season, making your shady corners glow.

When cooler weather starts to come on, gradually withhold water and allow the leaves to stay on until frost nips the tops, then go ahead and dig them up. Or, as the days start getting shorter and the leaves start fading and flower production slows, cut the leaves back to about five inches, and allow them to cure in an indoor room at room temperature. After curing, you can pull the remaining dried leaf stub off the plant. Store them in a peat moss filled perforated plastic potato bag or a box filled with moistened peat moss. Maintain enough space between the individual tubers to prevent them from touching. Keep the peat moss evenly damp, not wet. Store between 40 to 45 degrees. Check them periodically throughout the winter, and discard any rotten or shriveled tubers. If they appear to be drying out too much, barely spritz the peat moss with water just enough to get the medium barely damp again.

Dahlias

Another biggie in the summer bulb category is the Dahlia. Dahlias can be short or tall, or any size in between. They can be pom-pom in form, have single daisy-like blooms, be Dahlia flowered (naturally!), or cactus flowered. They come in many different styles and shapes. Colors run the spectrum, and again except for true blue, almost every color is represented.

These are sun lovin' ladies, so give them what they crave. They also like their well-drained soil, so please accommodate them. If your soil is heavy or too light, incorporate some good compost and other organic matter into the soil at least into the first four to six inches. What I know is that they are not that fussy, but for them, indeed for all our garden plants, good soil is the key to success. I add a slow released organic fertilizer, as recommended, and supplement this with organic fertilizer such as manure tea, liquid kelp, or fish emulsion.

Dahlias can go into the ground about a week or two before the last expected frost. This is for the unsprouted roots only, as young plants with top growth might get nipped. Wait to set these out. As with begonias, plant the roots buds up, about five or so inches deep. Plant them deeper if in sandier soils.

The larger varieties will need plant supports, so set out stakes or supports at the time of planting.

Pinch the new growth to encourage bushiness. I wait until 12 to 18 inches of growth appears. I do not grow dahlias for exhibition, so I don't follow the recommendations to disbud the flowers and keep them to one main shoot.

Keep the plants moist but not soggy. Adding mulch around your plants helps to conserve soil moisture, keeps the weeds down, and keeps their feet cool.

When frost kills the tops, cut the stems off to a little above ground level, keeping about six inches of stem to the roots. Let them cure in the ground about a week or so. Dig them up on a dry day, by removing the clumps gently, and allow them to dry a few hours before storing. Pack the roots again and store at about 40 to 45 degrees. Check them periodically for rot or shriveling, and discard any that have gone bad. If the storage medium is getting too dry, barely spritz the peat moss with water to moisten.

Cannas

Cannas are the Big Gals of the summer flowering bulbs. They are not shy at all, even the shorter varieties. They demand to be looked at, but they are not very demanding. These girls like it hot, and do well when the temperature rises.

If you want to get a jump-start on the season, start canna rhizomes in late March. You will need to use big pots, so be aware and plant them accordingly. Try to use the largest rhizomes for the fullest plants. Again, harden them off before planting them outside after the danger of frost has passed.

If you place them directly in the ground, again, place them in a well-prepared bed, about five to seven inches deep, depending upon soil type. Keep them watered and fed, and don't let them dry out in the heat of the summer. I have heard of people growing these plants in shallow water gardens, so they should not be allowed to dry out. I keep them reasonably moist. Keep the dead flowers picked off to continue the display. Do the same with cannas as with the other bulbs after frost kills the tops. Place them in a peat filled box, not touching each other, and store them at about 50 degrees.

If it's August in the Southern Great Lakes Region, then it's gladiolus time. Supermarkets, farm stands, and corner vendors sell these by the armload this time of the year. They are tall and stately in the vase, and tall and gangly in the ground. This is one plant that can be grown in rows, if you plan on having longer flower stalks. In my opinion, that is not very attractive. I would rather sacrifice a few blooms and a few inches in height by having them clustered in beds, fairly close together, than in unnatural looking rows. To each his own.

Gladiolus

Glads are formed by corms, a type of bulblike root. They have a pointed end, and naturally, an unpointed end. Plant them pointed end up. If your soil is heavy, plant them about four inches deep. If your soil is sandy, about six inches deep. If your corms are smaller, they will need to be planted more shallowly, about three to four inches or so deep. Space them in groupings about six inches apart in rows about 18 to 24 inches wide for maximum flower production. Mulch them. They will also need plant supports. Early in the season, when the plant leaves are about seven inches tall, hill up the plants a couple of inches up the bases to help give them support. Add organic fertilizer. Keep them weed free, mulched and watered for the maximum amount of flowers.

As the leaves die back, dig up the corms. Let them dry and cure in a well-ventilated place for a month to six weeks. Sort the corms, discarding any bad ones and keep the healthy corms in a cool place, about 40 to 50 degrees.

Caladiums

Caladiums are plants that are grown for foliage. They can be strap-leafed, or heart-leafed, the most popular variety. The patterns and colors of the leaves are almost iridescent. They do well in the dark corners of your shade garden, which is where they grow.

These are true tropicals, and it just doesn't pay to set them out in the soil until it has really warmed up. Late May to early June would be the time to set these tropical ladies out in the shady garden. You can get a head start on the season by beginning them indoors in April. Again, harden them off before setting them out, and don't allow them to dry out. The hotter the weather, the better they will grow.

Buy the largest tubers you can afford. Caladiums are classed as Mammoth (the largest), then in descending order: Jumbo, No. 1 large, No. 1 small, No. 2 small, and No. 3 small. The tubers have a large bud or eye surrounded by smaller buds. Carefully remove that large, usually central, bud or eye to encourage a fuller plant. If you don't, you won't get very many leaves on your plants.

Caladiums are not fussy, and folks like me who are challenged when it comes to finding the right side up on bulbs can just plant them any old way into the ground, they will grow. If you want to do it properly, however, plant them knobby side up. Depth should be fairly shallow, about two to three inches deep, according to size, and up to 14 inches apart for the Mammoth size. Again, I add a slow released organic fertilizer and incorporate lots of organic matter into their growing site.

Mulch the plants to keep the temperature of the soil around 70 degrees. If the soil temperature gets too high, these plants will lose some of their coloration. Don't keep them soggy, but don't allow them to dry out.

Before frost, the leaves will start wilting and fading as the soil temperatures drop. Dig them up, leaves and all. Allow them to dry in a shaded, warm area for about a week. Store them in a warm room, at about 70 degrees. An onion sack will do for storage.

There are so many other summer bulbs that can be discussed. This could go on and on. Hence the title, Rhizomes and Tubers and Corms, Oh my! There are so many wonderful summer bulbs out there, just waiting for us to plant them. Fool a few of them into growing in your garden this year!