Tuberous Begonia « Outsidepride

Let’s fast forward a few months from where our last week’s blog post left off — in the shady areas of the landscape, the Begonias have performed non-stop, giving a display of beautiful colors. Now, fall is approaching and Begonias naturally will go into a dormant period. During this dormant time, the tuberous roots must be lifted in order to survive the winter months.

Here are a few suggestions on how to successfully winter Begonia tubers:

To prepare the tubers for dormancy, gradually reduce watering and stop fertilizing at the end of August
Remove any flower buds that form during September in order to encourage dormancy and store energy in the tuber
Dig tubers after the foliage starts to turn yellow or after the first killing frost
Cut stems to about 5 inches and allow the tubers to dry indoors at normal room temperature, out of direct sunlight, until the remaining stems are dry and loose
Once dry, pull off any stems or roots and soil, but do not wash the tubers
Store the tubers in a plastic bag that has been perforated and filled with peat moss in a cool, dark environment
A temp of 40° – 50°F is ideal
An insulated attic, garage, or spare refrigerator work well
Periodically check the tubers for rot, softening or withering and discard bad tubers immediately

February is time to start the tubers that were stored. The Begonia tubers started in February should be ready to bloom in June. Here are the recommendations for starting tubers:

Plant the Begonia tubers in a flat of peat moss. If the tubers have no sign of disease, the peat moss they were stored in can be used. If there is some disease, start with fresh peat moss
Plant the tubers right-side-up in the flat and barely cover with peat moss. The upper side of the tuber is the side with a depression or hollow spot
The tubers are susceptible to rot, so keep the peat moss moist but not saturated. Do not let water accumulate in the hollow of the tuber
Place the flat in a temperature of 70°F and where the flat will be in indirect sunlight
Roots will develop from the bottom, sides and top of the tuber, and stems will form on the top as well
Within about 30 days, the stems will be about 1 inch in height
Repot the tubers into 6 inch pots or even the permanent pot that the Begonia will bloom in
Supplemental lighting or moving them to a bright window will help promote short, sturdy stems instead of tall, straggly ones
Small tubers = small plants and large tubers = large plants. The flower size does not have to do with the size of the tuber but by the number of stems growing out of the tuber. If the desire is to have large flowers, thin the stems when they are 3 inches in height. Small tubers should have 2 – 3 stems and large tubers should have 4 – 6 stems. Extra stems can be pinched off. If quantity of blooms is more desired than large blooms, do not thin the stems. This will form a bushy plant with lots of blooms and in addition to not thinning, pinch the tips of the stems in May
About 2 weeks before the end of frost season, begin to harden the Begonia plants off by moving the plants outdoors on warm days to a shaded and protected area. Bring them back in at night, and continue doing this and gradually move the plants in brighter light and expose them to more wind
Once frost danger has passed and the soil temperature has warmed, transplant the Begonia plants into baskets, containers or into the flower beds

How rewarding to start your own Begonia seeds and then to continue lifting, storing, and starting the tubers over. Gardening is such an art and what a pleasure to see your nurturing skills reap the reward of beautiful blooms and a color display that goes all summer long!

Question for the week: Do you store Begonia tubers from season to season?

By Kimberly Bell

Some flowers have wonderful popularity with gardeners and Tuberous Begonias are at the top of the list of favorites. They come in a range of colors and forms, with shades of red, orange, yellow, pink and white. Their blooms are single or double, plain or ruffled and often have many other distinguishing features.

Begonias are prolific bloomers, to say the least, and they cover their compact, branching stems and dark green foliage with bloom after bloom. They are also very versatile. Begonias are wonderful as a bedding plant and look great when planted in mass, but they are equally wonderful when grown in baskets and containers. Maybe the best thing about Begonias is that the do very well in the more shady areas where there is often little color. They thrive in areas where they receive bright light but little or no direct sun.

Begonias are native to the tropical areas of southern Africa and South America. Most Begonias that are available through garden centers or catalogs are hybrids, and the care and cultural requirements are the same for all. Tuberous Begonias are frost tender, so they should not be planted out in the flower bed until after danger of frost has passed. Likewise, the tubers need to be lifted in the fall and stored inside for the winter.

Begonia flower seeds are some of the smallest seeds in the world, nearly powder like. Growing Begonias from seeds is very rewarding, but it must be done indoors and the seed must be started in January to have plants ready to set out in the spring. To start the Begonia seeds:

Fill starter trays with fine-textured starting medium and moisten it
Press 2 – 4 Begonia seeds into each tray cell
Cover the trays with glass or plastic wrap to keep moisture in
Maintain a constant temperature of 70°F – if the temperature is not maintained, germination can take longer
Leave the plastic or glass on for 1 – 2 days after germination and then remove it
Thin the seedlings to 2 inches apart
Bright light is helpful in producing sturdy seedlings
When the seedlings become crowded transplant them to larger pots using well-drained potting mix
If seedlings look scraggly, pinch back growing tips to encourage more branching
Harden the Begonia seedlings for 10 days before planting outdoors

Summer Begonia care includes keeping the soil evenly moist, but it should drain well. Soil that is saturated can cause the stems to snap off at the base. Begonias are fairly heavy feeders requiring an application of a balanced (20-20-20) liquid fertilizer each month. Tidy the Begonia plants by trimming spent flowers. Grow the plants in an area that has good air movement to prevent powdery mildew.

The Beauty of Begonias, Part 2, will be next week, and I’ll share the steps to lifting the tuberous roots, winter storage, and setting the plants out the next spring.

Question of the week: Do you plant your Begonias in containers, in the flower bed, or both?

By Kimberly Bell