Tag Archive | Garden Education

Storing Tender Bulbs/Corms

By Kathy McCarthy

Do you love plants that have tender bulbs but think it is too much trouble to store them over winter? Hang on folks. The results may be worth your efforts and this is a great way to increase your supply. The directions are for plants I have been successful in storing.

Remember to dig carefully. It is important to loosen the roots gently, digging a few inches away from the plant. You want to avoid cutting or breaking the fleshy structure. Diseases enter through cuts and bruises.


A gladiolus ““bulb”” is really a corm, a swollen underground stem. A new corm forms on top of the old one. While this is taking place, small new cormels are produced from the base. Corms can be dug when the foliage begins to yellow or before a hard freeze. After carefully digging the corms, cut off the old leaves close to the corm. Leave the corms outside in the sun for a day or two and then spread out in a garage or similar place to cure, but not on a cement floor. This will prevent storage rot. After a few weeks of drying, clean them by removing the roots and outer sheath of corm. Remove and discard the old corm. Store the corms in a mesh bag and hang them out of the way in a cool well-ventilated area. I use a mesh onion bag and hang it in my basement. The small cormels can also be saved and planted the following year, but it will take a few years to produce blooming plants.


Dig the rhizomes in fall before the first frost. Remove the old stalks and gently brush off soil. They can be washed with a garden hose. Let them dry for a few days before storing. I store my rhizomes in a box filled with vermiculite. However they can also be stored in peat moss. Another way to store cannas is to leave the soil on the rhizomes and pile the clumps in a box. Cover with plastic and store in the basement or other dark, cool, dry area. I put the box on top of another container to keep it off the cement floor. Rhizomes must not freeze during storage. The temperature should be between 50 and 60 degrees. Never store canna rhizomes in a mesh bag, as this will allow the bulbs to dry out.

Calla Lily

Bulbs should be lifted out of the soil in late fall, but before the first frost. The bulbs bruise, so handle them carefully. Remove the excess soil by either washing or carefully rubbing it off. Dry the bulbs away from direct sunlight or wind for several days. Put them in a paper bag and store them in your basement or other dark, dry location. Like cannas, the temperature should be between 50 and 60 degrees.

Label and Check

When storing, I label the containers carefully. You can use a permanent felt marking pen to write directly on the fleshy root. I find it helpful to attach a sheet of information regarding planting time, depth, etc. to the container.

During the storage season, I periodically check for damaged or rotting material. Any damaged material is removed and thrown away. You don’’t want one bad ““apple”” to spoil the whole bunch.

Once spring arrives, you will be glad you saved those tender bulbs. If you have more corms, rhizomes and bulbs than you can use, think of your fellow gardeners and give them away.


Overwintering Geraniums

8387268_origSometimes you have a perfect summer with conditions that have contributed to the most beautiful container of geraniums you’ve ever had. What to do in the fall — let them die off and try again next year, or attempt to keep them over the winter? If you’re tempted to keep them, you have some options.

The perfect solution would be a cool, damp basement (can you say cellar?), where you could just hang them upside down. Shake the excess dirt from the roots, but leave all that clings. Loosely tie a string around the neck area, where the stem meets he roots, and use this to hang them from a rafter or beam. They should get good air circulation; be sure they don’t touch each other or anything else.

A dry basement — as long as it is cool (35º to 45ºF) — is a distant second choice. In that case, you will need to pot them up and they will need a place that’s light. They should be watered thoroughly about once a month, but let them go dry in between — they’re hardly growing.

No matter which way you store them, remove buds and flowers, where the disease botrytis hides, and any leaves that turn yellow. Cut the plants back to 6 inches after planting them outside next year.

Even thought your geraniums appear healthy, they could have picked up at least one of the many diseases that affect geraniums during the summer. When they are ready to go back outside, the geraniums will be stressed from their winter treatment, but any disease organisms will be just fine so the plants may not be as healthy as you expect. Keep a little extra in the gardening budget for replacements.

Fall Blooming Asters

by Dr. Leonard Perry, Horticulture Professor, University of Vermont


Aster amellus ‘Violet Queen’

There are many reasons to use fall-blooming asters in landscapes. There is much variety in this large group of hardy perennials, coming in various heights and showy flower colors. You’ll find selections in all shades of red, pink, purple, white, and even blue. They’re easy to grow, most are native, and they’re one of the main plants for bees, butterflies and other pollinators in the fall. They combine well with ornamental grasses, rudbeckia, and coneflowers. With so many to choose from, how does one begin? In addition to favorite colors, look for ones that best fit your growing conditions, desired habits, and disease resistance.

The starburst appearance of the flowers leads to the name “aster”, from the Greek word for star. Asters give their name to the large composite family—Asteraceae—that of sunflowers, dahlias, daisies, zinnias, and similar flowers. The asters all used to be grouped together into one “genus” (Aster), but thanks to recent botanical research they’ve been regrouped with names more suited to botanists than gardeners. So for instance, although the New England aster genus is now changed (Symphyotrichum), the species name has remained the same (novae-angliae).

Generally, most asters prefer moist, well-drained soil and full sun. There is a range of species, however, that can be grouped by their native environments and corresponding garden preferences. The first group prefers rich, moist soil in full sun. These include the species native to meadows, prairies and marshes such as the New York (S. novi-belgii), New England (S. novae-angliae), and flat-topped (D. umbellata) asters. They prefer steady moisture. Ones that prefer moist soil, but can tolerate dry sites, include the sky- blue (S. oolentangiense), heath (S. ericoides), calico (S. lateriflorum), aromatic (S. oblongifolium), and silky (S. sericeum) asters. Tatarian aster (A. tataricus) in this group, a Siberian native, is quite adaptable to various soils.

The second group of asters also prefer full sun, along with cool nights, and very well-drained soil. This is because they are native to seashores and mountains where soil drainage is excellent. They may be short-lived over only a few years,particularly if conditions aren’t just right. In this group you’ll find the European Michaelmas daisy native to Asia Minor (A. amellus)—a name often given to many asters as they bloom around this Christian  holiday of September 29. Others in this group are the Frikart’s (A. xfrikartii) aster, of garden origin, and East Indies (A. tongolensis) aster native to western China and India.

The third group of native aster species tolerate shade (under 4 hours direct sun per day), but bloom better in part shade (4-8 hours of direct sun). The blue wood aster (S. cordifolium), Drummond’s aster (S. drummondii), white wood aster (E. divaricata), and big leaf aster (A. macrophyllus) are in this group. Although they prefer moist soils rich in organic matter, they will tolerate some drought.

In perennial trials at the Chicago Botanic Gardens (www. chicagobotanic.org/downloads/ planteval_notes/no36_asters. pdf), 119 asters were evaluated over six years. They were rated based on flowering, health, habit, and hardiness. In this USDA zone 5 site (-10 to -20F average winter minimum), seven asters stood out with five-star ratings. These top asters included ‘Jin Dai’ tatarian aster, white wood aster and its cultivar (cultivated variety) ‘Eastern Star’, ‘Snow Flurry’ heath aster, calico aster and its cultivar ‘Lady in Black’, and ‘Raydon’s Favorite’ aromatic aster. For a rock garden or low wall, where cascading stems are desired, ‘Snow Flurry’ would be a good choice. For perennial gardens and naturalistic landscape masses, good choices would include asters with bushy habits—‘Jin Dai’, ‘Lady in Black’, or ‘Raydon’s Favorite’.

In addition, there were 19 asters that rated good, with four stars. These good asters included a couple of New England asters— the rosy pink ‘Harrington’s Pink’

and deep pink ‘Honeysong Pink’, and three New York asters—the light lavender ‘Blaubox’, lavender- blue ‘Climax’, and purple-pink ‘Rosenwichtel’. Most selections you may find of the asters are in the New York and New England species. Perhaps the reasons that more didn’t rate more highly relate to habit and potential problems. Aromatic asters tend to be less problem-prone, and good alternative choices.

New England asters can get to four to five feet tall and fall over under some conditions, particularly low light. Cutting them back in early summer by one third to one half will make them more bushy, with no need to stake.


Aster ‘Purple Dome’

One of the more recent introductions of New England asters, and one of the most popular asters, ‘Purple Dome’ came from the Mt. Cuba Center and gardens in Delaware. It is violet-purple and low, only growing to about 16 inches high and about 2 feet wide. This makes it a good choice for fronts of borders, along walks, massed, or even containers. It bloomed over two months in Chicago, from early September to early November. ‘Vibrant Dome’ is a bright pink sport of this compact cultivar, not in these trials but popular and available.

‘Purple Dome’ is a good example of how resistance to diseases can vary by site. Often considered to have excellent resistance to powdery mildew, in the Chicago trials this cultivar was only rated as fair.

Asters may get rust or powdery mildew diseases on leaves. The former was seen more on the New York asters in the Chicago trials, while the latter disease was seen more on the New England asters. Giving good air circulation around plants, and disposing of leaves in the fall (not in the compost bin) will help lessen these. There are several sprays, organic and synthetic, that can be used for these too. A main destructive insect of asters may be the lacebug, a small grayish insect that appears in midsummer and sucks the plant juices from the undersides of leaves, primarily of the New York and related types. Leaves turn yellowish and eventually brown and fall off. Organic or synthetic insect sprays can be used for control. Read and follow all label directions for best control, and safety for you and the environment.

Deer and rabbits can be quite fond of asters, too. There are repellent sprays for these. Low fencing for rabbits, and deer netting for these may be needed if repellents don’t work. Several asters have been bred as alternatives to fall garden mums, including the lavender ‘Ariel’, violet ‘Celeste’, and the purple ‘Pixie Dark’. Results from the Chicago trials show these only live a year or two, so should be grown as annual flowers. Since the New York asters have problems, and are short-lived, they are not recommended either, even though commonly found.

Keeping asters healthy during the growing season—in part, growing them under the right conditions—will go a long way toward helping them survive the subsequent winter.


Keep your Caladiums

Starr_071024-9740_Caladium_bicolorAre your caladiums so beautiful this year that you can’t face the thought of getting rid of them when the summer is over? Why not try to keep them until next summer?! They can be left in the garden into fall so that the leaves can continue working and the tuber can continue to grow larger. However, once frost is in the forecast, don’t wait — just dig, taking up the whole plants or only the tubers.

To winter over a caladium, put the tuber into storage immediately or pot up the whole plant and place it in a brightly lighted windowsill. By late January, the caladium is going to look tired and will need to rest before the tuber is repotted in the spring or planted in the garden after the soil has warmed up. Chop off the foliage, knock off the soil, and let the tuber dry at room temperature. Any condensation will encourage bacterial rot. Store the tuber in dry vermiculite or in a mesh bag (like an onion bag) in a dry place, ideally at 70º to 75ºF but never below 50º, making sure there is good air circulation. Remember: it needs to be stored dry!!

Caladium is an extraordinary foliage plant. Its leaves can be white with narrow green borders or combinations of white, green, and rosy pinks, in pale to outrageous patterns that approach a third grader’s first attempt at stained glass. Most caladiums are hybrids of Caladium bicolor or C. picturatum, native to the tropics of the Americas and the West Indies. Plants can be costly, but tubers are inexpensive so you can just say goodbye at frost time if you like.

Lilac Woes

Did you plant a lilac bush and have lovely flowers the first year and nothing since then? Or maybe you’re not getting the flowers that you used to get from your established lilacs?

According to Jack Alexander, the chief plant propagator at the lilac-magnificent Arnold Arboretum at Harvard University, newly planted or transplanted lilacs tend to have transplant sulks. Most spring-flowering shrubs, lilacs included, form flower buds the previous year. That initial display you see when you buy new shrubs was set when the lilac was still comfortably at home in the nursery. When it was moved, the disturbance set it back. Give it a bit more time, and whatever you do, don’t move it again!

flower-356176_960_720Common lilacs (Syringa vulgaris) and the French hybrids based on them are especially sensitive in this regard. If you’re the type who likes to move the furniture around, try planting ‘Miss Kim’ (a cultivar of S. patula). She’s a bit less fussy about an occasional relocation.

‘Miss Kim’ is easy to find at nurseries, as are a good number of S. vulgaris varieties and cultivars. But for the widest selection of colors, fragrance, and bloom times, mail order is the way to go.


Lilacs have to grow for a few years before they start flowering. After that, they bloom in spring on year-old wood, the stems that grew from the older branches during the previous summer.

Pruning consists mainly of removing elderly trunks and clipping off seed heads within reach. But if you want to cut back young growth, the proper time is right after flowering. It should be done as soon as possible, and no later than three weeks after petal fall.

Still not getting Flowers?

If you are not pruning too late or cutting off all of the new growth, the problem may be too much fertilizer, which could push vegetative growth at the expense of flowers. Or, maybe the problem is a lack of light. Lilacs need plenty of sun to flower well, and shade is the most common culprit when mature bushes fail to bloom.

Remember, too, that if you go through a summer of little or no rain, the plant will be unable to set buds for next year so you can expect little or no flowering the year after a drought.

Too Many Tomatoes?

by OCMGA Master Gardner Mary Learman

This is a fantastic recipe for the glut of tomatoes in the summer. I like to use it for that last crop of the year, when there isn’t enough for a big canning session but too much to eat.

Untitled1Passata is such a useful store cupboard item to use in all sorts of savory dishes. You can use it as is for a quick pasta dish, pizza sauce, add it to premade tomato sauces and soups for an authentic taste. If you are all canned out, simply pour the finished passata into containers and freeze to use in the winter. Add some to risottos, gumbos, soups, stews and polentas for a rich undernote of harvest.

Roasted Tomato Passata.

To make two 16-oz jars, you will need:-

4 ½ lb. ripe tomatoes
7 oz. shallots
3-4 garlic cloves, peeled and thinly sliced
a few sprigs of herbs of your choice – basil, thyme, oregano, rosemary
1 t. sea salt
½ t. black pepper
1 t. sugar
2 fl. oz olive oil
2 T. commercial lemon juice

Preheat oven to 350°F.

Cut the tomatoes in half and place then cut side up in a single layer in a large roasting pan. Scatter the shallots, garlic, herbs, salt, pepper, sugar and oil over the top. Roast for about 50 minutes to one hour, until the tomatoes are well softened. Remove from the oven and puree using a food mill.

Put the tomato puree into a pan, add the lemon juice and bring to the boiling point. Pour into hot sterilized jars and seal. Water bath for 35 minutes.

Use within one year. Once opened, refrigerate and use within a few days.

Always practice safe canning – http://nchfp.uga.edu/publications/publications_usda.html will answer all your questions.

Garden a little bedraggled?

If summer’s heat and drought conditions (at least at my house) have your garden hanging it’s head, perk things up with some tips for keeping borders beautiful even when stressed.


Goldenrod, Black-eyed Susans, Joe Pye Weed are all drought tolerant plants

Watering makes a HUGE difference. Keeping plants watered is essential for a good-looking garden, but it can turn into a chore when temperatures are high and it doesn’t rain. Save yourself time and money with these watering tips:

  • Easy irrigation – a simple soaker hose is one of the most basic ways to irrigate. Lay a porous hose down on your garden, and it’ll weep water onto the soil. Because you’re applying moisture right at soil level, there’s less loss due to evaporation. Cover your hose with a couple of inches of mulch to protect it from the sun’s UV rays and help it last longer.
  • Check your irrigation system to make sure all zones are programmed, then turn it on only when it’s needed.
  • Sometimes it’s easier to water with a hose. Avoid dragging it all over the yard by grouping containers together.

Stop weeds and drought stress. Plants that aren’t stressed by aggressive weeds or lack of moisture are healthier and bloom longer with more flowers. Ideally, you’ve mulched in spring, but it’s never too late to put some down.

  • One of the best things you can do to keep plants fresh in summer is to apply a 2- to 3-inch layer of some type of organic mulch. If it’s looking a little thin or matted down in your garden, use a leaf rake to fluff what’s there and top it off, if needed.
  • If drought stress has already affected your annuals or perennials and you notice brown and crispy flowers or foliage, go ahead and cut off what’s damaged. Sometimes the whole plant looks bad. In that case, prune all the dead-looking stuff out. Make sure there’s enough mulch and water so the soil stays evenly moist for the rest of the season. Many perennials will start growing again from the crown in a week or two. Some plants, such as bleeding heart, will go completely dormant, but grow again the following spring.

Get rid of spent blooms. Deadheading often — even daily — will keep your garden looking its best. You’ll get a faster repeat bloom and avoid unsightly spent blossoms hanging around. Deadheading encourages your plant to produce more flowers and store energy for winter instead of forming seed heads. In fact, some people don’t like the look of hosta blooms so they cut them off below the foliage as they emerge.

Heat stress and lack of water can make plants susceptible to pests and disease so keep a close eye on your plants and act quickly if you spot trouble!