Bulbs

Do You Dig Dahlias?

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By Dawn Pettinelli, UConn Home & Garden Education Center

Dahlias in a bed at Enders island
Dahlias at Enders Island. Photo by dmp2024

A couple of weeks ago, I was fortunate to visit the spectacular dahlia gardens on Enders Island in Mystic. For those unfamiliar with this retreat, an 11-acre seaside estate was donated to the Society Edmund by Mrs. Alys E. Enders in 1954. This Roman Catholic religious community offers ministry, retreats and respite to many. The grounds are open to all for contemplation or just unbound appreciation of nature and horticultural beauty.

Gardeners will delight in the gorgeous, well laid out garden rooms but especially be entranced by the vast array of dahlias. The gardens at Enders Island are filled with over 300 varieties of prize-winning dahlias in all colors (except blue), shapes and sizes imaginable. A Dahlia Preservation Trust was established to preserve the dahlia collection that is rated as one of the largest in New England.

Any of us growing dahlias while appreciating their cheery, attractive blossoms lasting long into the fall, do realize they are not winter hardy, even with milder winters attributed to climate change.  Dahlias are native to Central America. In fact, they are Mexico’s national flower. Those wishing to save the tuberous roots for replanting next year, must dig them up and store them over the winter.

Ideally, gardeners should wait until a frost blackens the foliage. Then, if possible, wait a week so any carbohydrates left in the above ground tissue can make their way to the roots to enable good sprouting next spring when the tuberous roots are replanted. This has been a particularly confusing fall to both plants and gardeners. Frosts have hit some areas but often not severe enough to affect all plants and dahlias in more protected sites are still blooming their heads off, a trait most appreciated by pollinators such as bees.

On the other hand, it is November. Time to reign in gardening activities and begin preparations for the holidays. What’s a gardener to do?

Since my plants were losing bottom leaves to disease and looking a little ragged, I just decided it was time to dig them and move the tuberous roots into the cellar. Before digging any dahlias, be sure to note their names. If tags were not written out when planting, make them out now if color and flower type are important.

Cut back stems to 2 or 3 inches and carefully dig the tubers starting at least 8 inches away from crowns so tubers do not get sliced or speared. Use a spade or pitchfork but dig in carefully. This year the soil is so dry that it was not necessary to leave the tuberous roots in the sun for a few hours so the soil clinging to them could dry and be shaken off. Every one I dug up was dry enough so that practically no soil clung to the roots. Each was placed in a separate container with repurposed labels.

Dahlia tubers with a white tag
Dahlia tubers tagged for storage. Photo by dmp2024

Perusing through online sources, many suggest washing tubers off with a hose and letting them dry before storing. I have let them dry out in wet falls and shaken dried soil from them before storing but have never hosed them off. Maybe follow the approach that makes most sense to you. If any remaining soil is washed off, the tuberous roots should most likely be stored in lightly moistened peat moss or other slightly damp organic material, so they will not desiccate over the winter. For me, leaving a bit of soil around the roots that are stored in pots in the cellar over winter helps to keep tubers from shriveling with only a sparse sprinkle of water once or twice a month.

When happy, dahlias will multiply but it is probably best to leave the whole clump together and separate it before planting next spring when multiple buds or eyes can be seen. Keep the tuberous roots at 45 to 55 degrees F and check every 2 to 3 weeks for signs of decay or desiccation.

For an early start, the tuberous roots can be set into beds usually by late April unless unseasonably cold weather is predicted. If you have questions about overwintering dahlias or for other gardening questions, contact the UCONN Home & Garden Education Center, toll-free, at (877) 486-6271, visit their web site at www.homegarden.cahnr.uconn.edu or contact your local Cooperative Extension Center.

Coax Bulbs into Bloom for Late Winter Color

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By Dawn Pettinelli, UConn Home & Garden Education Center

Tulip bulbs on display in the store
Photo by dmp2024

Autumn adorns us with vibrant leaves, whispering grasses, warm colorful mums, colorful cucurbits and sun-bleached cornstalks. Time spent cleaning up the gardens and yard now will be appreciated come spring. A favorite fall task is selecting and planting bulbs for spring color, accent and scent. When doing so, purchase a few extras to force into bloom.

The word, forcing, is rather harsh. I’d like to think of it more as coaxing or gentle persuasion. What we’re really doing is subjecting the potted bulbs to a shorter simulated winter so they will burst forth into bloom weeks earlier than if planted in our gardens.

Many species of bulbs can be forced. Hyacinths, tulips and daffodils are most popular. When visiting your local garden center to purchase bulbs, look for varieties that say ‘Good for Forcing’. Most hyacinths force well. Tulips and daffodils range greatly in size and bloom time. Usually the smaller, earlier, shorter varieties can be brought into early bloom most successfully.

Minor bulbs such as crocuses, snowdrops, scilla, Siberian squills, chionodoxa, netted iris and wood hyacinths are also great choices for forcing. As a general rule of thumb, these smaller bulbs need a minimum of 8 to 10 weeks of chilling versus the 12 to 14 weeks the larger bulbs may require.

Select pots with adequate drainage. Typically, 6-to-8-inch bulb pans or azalea pots are used. This type of pot is wider than deep. Look at the size of your bulbs first as one generally wants pots twice as deep as the height of the bulbs. Realistically any size pot could be used as long as it has adequate drainage.

Use a soilless, commercial potting media and moisten it with warm water so that it is damp but not saturated before potting up your bulbs. For a 6-inch bulb pan, plan on fitting in 3 hyacinths, 3 to 5 daffodils or 5 to 7 tulips, depending on the size of the bulb, or 10 to 12 minor bulbs. Yes they will be a bit crowded but it’s only temporary and they will give you a better show.

Fill the pot about halfway or so with the potting mix and set in the bulbs so that the minor bulbs will be slightly below the soil line but the larger bulbs have their noses sticking out of it. Give the pots a good watering but let them drain so no water is running out.

Then place them in a dark place with temperatures ranging from 33 to about 34 degrees F. Often a shed or unheated garage works well. Some folks may have a cold section of cellar, perhaps in the bulkhead. I find that placing them in an old aluminum trash can in the garden shed works well as mice can’t get in the can to nibble on them. Others have dug trenches in the garden in which the pots are placed and covered with leaves. Apartment dwellers could place the pots in a plastic bag in the refrigerator if room permits.

Pots should be checked every 2 to 3 weeks to see if watering is necessary and to check for root growth. Bulbs will be ready to move inside once white roots are evidenced through drainage holes and shoots begin to emerge from the bulbs. When these two growth signs are noticed, pots can be brought into bright, indirect light when the temperatures stay from 50 to 60 degrees F. It usually takes 3 to 4 weeks from when bulbs are brought inside until when they bloom.

Hyacinths forced indoors
Photo by dmp2024

At this time, they would appreciate a light fertilizer application. A typical houseplant fertilizer at rates listed on the package would suffice. Turn the pots regularly so the plants do not lean towards the light. Once you see the flower stalks form, the bulbs can be brought into warmer temperatures where their blossoms can be enjoyed. Keep in mind that the higher the temperature, the quicker blossoms will both open and fade. If possible, keep them cool or at least move the pots into cooler areas at night.

In some cases, the bulbs fail to bloom and this may be due to storing bulbs before or after purchasing at too high a temperature, not long enough chilling temperatures, lack of adequate moisture, or bringing the forced bulbs into high temperatures too quickly. Most of the time success is achieved and enjoying the sights and scents of spring flowering bulbs inside our homes in late winter is quite a reward for not a great deal of effort.

If you have questions about forcing bulbs or any other gardening questions, feel free to contact us, toll-free, at the UConn Home & Garden Education Center at (877) 486-6271, visit our website at www.homegarden.cahnr.uconn.edu

 

Watch for Bulb Diseases

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Dr. Nick Goltz, UConn Home & Garden Education Center; UConn Plant Diagnostic Lab

Gardens in New England come to life in spring thanks, in large part, to bulbs! Spring bulbs are reliable, perennial color-bringers and seem equally at home in landscapes and containers. Daffodils (Narcissus spp.), grape hyacinth (Muscari spp.), and tulips (Tulipa spp.), are just some of the bulb plants that grace our gardens this time of year, and they remind us that the blooms of summer alliums aren’t far behind. While these plants might seem effortless to grow, they are not without their fair share of disease issues!

Purple streaking and weak root systems associated with Fusarium rot.
Purple streaking and weak root systems are symptoms associated with Fusarium rot. Ed Kurtz, budwood.org

One common disease of bulbs we see here in Connecticut is Fusarium wilt and bulb rot.

Bulbs generally prefer average to loamy soil with good drainage. When planted in clay soils or following long periods of rain in early spring, however, they are susceptible to rot diseases caused by fungal pathogens such as those in the genus Fusarium. The various wilt and rot diseases caused by Fusarium species can be destructive and sometimes difficult to control. Symptoms include wilting, brown lesions at and below the soil line, vascular discoloration, bulbs that are soft or spongey, and, especially with garlic (Allium sativum) and relatives, a purple-red discoloration of bulb tissue. Plants affected by this soil-borne fungal disease do not recover, so it is wise to be proactive with management and prevention.

If your bulb plants do not emerge properly in the spring or emerge but wilt soon after, fail to flower, or display other symptoms associated with root rot diseases, pull them up and throw them away! Fusarium and similar fungal pathogens often survive the winter in the soil on diseased plant tissue from the year before, so it is important to keep your garden clean and to not compost diseased plant tissue, as most home compost bins do not reach temperatures necessary to kill pathogens. Fungi like Fusarium thrive in soggy soils, so do your best to prevent flooding and standing water where bulbs are planted. There are no fungicides that will completely control or eradicate Fusarium in a landscape, but some are helpful with preventing infection of healthy plants. Remember to always wear protective equipment and follow label rates and instructions if you choose to apply fungicides.

Symptoms of tulip fire, Botrytis tulipae, on tulip flower and leaves.
Symptoms of tulip fire, Botrytis tulipae, include leaf spots on leaves and flowers, often with dark boarders resembling burn injury, lending the common name. Sandra Jensen, Cornell University, Bugwood.org

Another common fungal disease of bulbs grown here in the Northeast is Botrytis gray mold or tulip fire. Fungi in the genus Botrytis cause disease symptoms on many different host plants. Though it is often called “gray mold” when associated with other plants, for tulips, the disease is usually called “tulip fire” due to the spots it causes on leaves and flowers, often with dark borders resembling a burn.

Botrytis fungi are very common and are capable saprophytes, meaning they feed on dead or decaying tissue and contribute to nutrient cycling in the environment, but can be problematic in managed landscapes. To cause disease, Botrytis fungi must first colonize and get nutrients from dead or declining plant tissue, such as fading flower petals, over-ripened fruit. Once the fungus is established in its host plant, it becomes more aggressive and invades healthy plant parts, causing brown lesions and decay.

To prevent Botrytis gray mold and tulip fire, try to encourage good airflow around your plants. Many people plant their bulbs closely together, like eggs in a carton, but this can make bulbs susceptible to tulip fire over time when treated as perennials. Dig up your tulips when they appear crowded, and each year when dealing with a potential disease issue. Inspect bulbs before you plant them again, and discard bulbs that are not firm, discolored, or otherwise do not appear healthy. Rotate to new locations and avoid planting consecutively in the same spot if there has been a history of disease there.

If you have questions about growing bulb plants, are dealing with a plant health issue, or regarding other gardening topics, feel free to contact us, toll-free, at the UConn Home & Garden Education Center by emailing ladybug@uconn.edu. You can also call us at (877) 486-6271, visit our website at www.homegarden.cahnr.uconn.edu, or contact your local Cooperative Extension center.

Tips for the February Gardener

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Tips for the February Gardener

By Dawn Pettinelli, UConn Home & Garden Education Center

Pothos with yellow leaves
Photo by dmp2024

February is a tough time for gardeners. Days are getting longer but the cold temperatures, and in many cases, snow, are keeping us inside. This is a good month to provide houseplants with a little TLC before the weather warms and the gardens beckon.

If possible, bring your plants one by one to the kitchen sink. Give them a thorough grooming by removing any dead or off color leaves. Trim back wayward or undesirable growth. Then give them a good rinsing under the faucet or use a wet cloth to wipe dust off of their leaves. For plants with hairy leaves, like African violets, a soft brush could be used to clean their leaves. Wash their saucers out before setting plants back.

Plants that have outgrown their pots can be repotted at this time. Usually, plants would be moved up to a pot that is an inch or 2 wider. Loosen or trim roots if they are growing in a circle or very dense. An all-purpose potting mix can be used for most plants but specialized mixes for plants like cacti and African violets are also available.

Your amaryllis has probably finished blooming by now. Cut off any spent flowers. Some people like to leave the stem until it yellows as it can photosynthesize but I generally remove the whole stalk after flowering. If you want plants to rebloom next year, the foliage needs light, water and nutrients to grow. Set your plant in a bright location and fertilize monthly starting in March. Plants can be moved outdoors after the danger of frost has passed either in their pots or set them into the ground in a part shady spot. Bring inside in mid-October and let the bulbs go dormant in a dark, warm area for about 8 weeks and then repot for another season of striking trumpet-shaped blooms. Some cultivars do not require a dormant period.

Check on any tender bulbs that you have in storage. Dahlias and tuberous begonias can shrivel if they dry out too much. They are usually stored in some barely moistened peat moss or wood shavings. Sprinkle with a little water if they are on the dry side. Also, this would be a good time to check on any winter squash, potatoes or other vegetables that you’ve been keeping. Use them up before they spoil.

Time spent perusing garden catalogs, either in print or digital format, is a great way to get through cold, winter days. When making out a seed order, don’t forget to note what seeds you have leftover from last year. Most seeds retain their viability for at least a year. It’s always a good idea to plan out the vegetable garden so you know what’s going to be planted where, and when. Last frost dates for your area can be found at: https://garden.org/apps/frost-dates/. The UConn Master Gardener program is offering a Garden Journal with tips on how to plan and maintain your flower and vegetable gardens and plenty of room for you to make notes. To order go to: https://mastergardener.uconn.edu/2024/01/30/garden-journals-available/.

Most of us recognize the benefits of buying local when it comes to produce and other Connecticut grown products but did you know we have at least 5 seed companies in Connecticut. They include Select Seeds (www.selectseeds.com), the Chas. C. Hart Seed Co. (www.hartseed.com), the Heirloom Market at Comstock Ferre selling Baker’s Creek Heirloom Seeds (www.heirloommkt.com), John Scheppers Kitchen Garden Seeds (www.kitchengardenseeds.com), and New England Seed Company (www.neseeds.com). Be sure to see what they have to offer either online or at various retail locations.

If you need a floral fix to get you through to spring, stop by the CT Flower and Garden Show at the Convention Center in Hartford, Feb 22 -25. Visit the UConn Home & Garden Education Center’s booth for a free pH test (bring a half cup of soil) and answers to your gardening questions. A blooming time can also be had at Elizabeth Park’s Greenhouse Bulb and Plant Show, March 1 – 9. Since spring can’t be here soon enough, you’ll just have to go to where the flowers are blooming!

For your gardening questions, feel free to contact us, toll-free, at the UConn Home & Garden Education Center at (877) 486-6271, visit our website at www.homegarden.cahnr.uconn.edu or contact your local Cooperative Extension center.