Digging In: Advice on Watering Plants in Big Containers, Photinia Disease
Thursday, June 11, 2009
Q Can you recommend screening plants
to be grown on our sunny balcony in containers? The balcony is also windy.
We have lost boxwood, a crape myrtle,
a yew and a maple. All were in large planters with good drainage. We watered them daily. Was that too much?
A All of the plants you mention are quite resilient. The crape myrtle may have been injured during the winter. If you grow another, you should try to find a place to store it in winter. An unheated garage would be ideal for preventing cold injury to the roots.
If the containers are large enough, you should not have to water the plants daily. Big containers will give you another key advantage: Greater soil mass means fewer rapid changes in soil temperature, which is really hard on potted woody plants in winter. A pot or tub that can hold a cubic yard of soil is a good starting point.
You shouldn't water any container plants on a fixed schedule. Check the soil first. If it is moist to the touch, you can delay watering, particularly in cool weather. However, during the height of summer, you may need to water twice a day. In spring and fall, you may not need to water for a week or longer.
Other resilient plants that you may want to try are dwarf Hinoki false cypress, red twig dogwood and Silver Spreader or Grey Owl juniper.
Scott Aker is a horticulturist at the U.S. National Arboretum.