Saving Your Begonias

Saturday, September 27, 2008 04:18 AM

Most gardens and landscapes in our area have now been affected by a killing frost. With the killing frost comes the chore of bringing tender bulbs such as tuberous begonias indoors for the winter if you want to save them and replant them again for next year. If they are left outside over the winter they will freeze and will not re-grow next spring.

By over wintering your tuberous begonias you not only save money by not having to buy new tubers next spring, but you will also get larger tubers for next spring which in turn means more flowers!

Tuberous begonias that are grown in a container can be over wintered by bringing the pot indoors where the temperature is just above freezing. Stop watering the container allowing it to go dry.

After a couple of weeks cut back the blackened foliage to 6 inches from the tuber, and then after a few more weeks the remaining foliage with dry up and fall off. Continue to store the plant in a cool area where temperatures are 5-10 Celsius. In February/March begin to water it and place it in the light so that it will start to grow again and by next summer you should have a beautiful flowering plant again.

If you have had the tuberous begonia in the same pot for more than 2 seasons it should be taken out of the pot and if you have tuberous begonias growing in the flower bed you will need to dig them out of the soil. Dig them out carefully so as not to damage the tuber and place the tuber in a cool location for 2 weeks. After two weeks cut back the foliage to within 6 inches from the tuber and carefully shake off as much of the soil as possible and then in a few more weeks the remaining stem will dry and fall off. At this time dust the tuber with bulb dust and store in a container filled with either dry sand or vermiculite in an area where the temperature is 5-10 C.

In February take the tuber out of storage and re-plant it by placing it in a 4 inch peat pot (larger if the tuber is bigger than 4 inches) that is filled with a good quality potting soil.* Do not plant the tuber too deep, ½ inch below the soils surface is perfect. Always plant the tuber with the hollow side up as this is the top side, and when watering you want to be careful not to get water in the hollow part of the tuber as this can cause it to rot, so always water along the outside edges of the tuber. After the tuber is planted give it a good drench of water and place it somewhere, where there is lots of light and the temperature is around 20 Celsius. For the best results you could place it in a mini indoor greenhouse or place a piece of plastic over the container and then when you see the little pink growth buds appear, remove the plastic or greenhouse.

Only water the tuber when the soil becomes dry until it begins to show some growth, after which you then keep the soil moist but not wet. After the plants new growth reaches 3-4 inches tall you can transplant it into a larger pot. To create a strong stocky plant you should not keep it too hot but rather in a cooler area of the home. Also rotate the plant every few days so that it receives even light and won’t grow towards one side. As the sun gets hotter you will want to keep the plant out of the hot midday sun to prevent the leaves from burning.

Tuberous begonias are a shade loving plant so place it in a north or eastern window. Towards the end of May or beginning of June when there is no risk of frost you can place or plant the tuberous begonia outside for another summer of beauty.

*Note: You can use other containers to start your tuber but by using a peat pot you do not have to worry about damaging the root system by taking it out of the container to transplant it into another container or the ground at a later date. The planted tuber remains in the peat pot and the entire pot with the tuber is then transplanted to where you want it grow for the summer season after all risk of frost has passed.

-Jos

Jos Van Hage owns and operates two Art Knapp Garden Centres in Prince George: