Thanks for listening!
We aren't always able to answer everyone's texted questions on the air, so we try to post a few along with answers here in the Yard & Garden News blog. Remember that you can always visit the U of M Extension Garden website for loads of gardening resources. And feel free to share your gardening stories here by clicking on "Leave a comment" above.
Hope you join us and our host Denny Long every Saturday, 8-9am, on WCCO Smart Gardens and happy gardening!
American Bittersweet 'Autumn Revolution': Thanks to to listeners last week who shared via text the bittersweet cultivar 'Autumn Revolution' (Celastrus scandens 'Bailumn') developed by Bailey Nurseries, Newport, MN. This bittersweet has 'perfect' flowers - male and female parts on each flower - unlike the species bittersweet which has separate male and female flowered plants.
Overwintering perennials in containers: Perennials are best overwintered planted in the soil. However, they are used in container plantings and some listeners have asked how to overwinter them. There's no guarantee, but certainly worth a try. The goal is to allow the plant to gradually go dormant as it would in the ground, but protect the roots from cold air as they would be in the soil. Try overwintering these plants by tipping the container over onto the soil and covering in leaf mulch, wood mulch or straw. Or try placing the container in a cool location such as a cellar or heated garage (about 40-50 degrees F.) If it's not too much work, you could also dig a hole in your garden or compost pile and bury the container up to its rim, covering the top of the soil with straw or leaf mulch. Do not water them, but allow them to go dormant. When the weather warms up and you start to see plants emerging in your garden, tip the container over / move the container out into the sun and start watering.
Do pileated woodpeckers cause oak wilt? This was the first time someone has asked me this - and I truly never thought about it! Oak wilt is spread overland by sap-feeding beetles, and underground by infected roots grafting onto healthy roots. I could find nothing that indicated woodpeckers or other birds spread oak wilt. As home owners, be alert to the signs and symptoms of oak wilt, and avoid pruning oaks April - June or whenever you see the active beetles. Remember that dates provided are recommendations - you still need to be vigilant in your yards and gardens. For more on oak wilt: MN DNR
Dividing perennials: If you are considering dividing your perennials - including hardy hibiscus (Hibiscus moscheutos) as asked by one listener, here is a terrific publication / chart Dividing Perennials you can use as a reference. Notice that there are some perennials that should not be divided - and Hibiscus moscheutos should be divided every 10+ years according to the above publication. Make sure your planting location is large enough for your selected plant to grow to full maturity.
Must I wait till freeze to dig calla and canna bulbs? Calla and canna are summer-blooming tuber-like rhizomes and really quite stunning plants. However, unlike bulbs like tulips and daffodils that require cold treatment, calla and cannas do not survive our winter temperatures and must be dug in the fall and re-planted each spring. Dig them now as you don't want to risk the rhizomes freezing. According to our Extension publication Calla and Canna Lilies: "They bloom mid-summer to frost. In the fall, dig up the rhizomes, cut the stems back to 2-3 inches, and let them dry. Leave them in a box in a cool part of the house where they will not freeze, such as a basement where the temperatures range between 40-50 degrees. Every few years, the rhizomes may be divided. When dividing, each piece must have an eye or growing point on it. Let the cut-up rhizomes dry for a few days before planting them."