I have three hosta plants on the north side of my house. I planted them in a raised bed four to five years ago. The first two years or so the plants grew large and had flowers. The last two to three years the plants have been quite small and had no flowers. The leaves are still nice and green, but they just appear to be stunted. They are in the shade most of the day with some sun late in the afternoon. What can I do to get them to grow like they use to?
Hostas are usually pretty reliable performers in the landscape so long as you keep the slugs and deer away. This year has been an especially good one for most of the plants I’ve seen. One potential problem would be that your planting bed has become too shaded. While hostas certainly grow well in partial shade, they need a certain amount of light to thrive. If the surrounding trees have grown over the last five years, they may be shading out your hostas. There is also the possibility that your plants are not receiving adequate moisture, which would stunt your plants. Since your leaves still look nice and green, I would rule out most diseases of which I’m aware. Hostas typically don’t need dividing, but I would dig them up, put some compost in the bed and re-plant them in a spot with morning sun and keep them well watered.
Cherry trees, beautyberry and weeds
What is the natural lifespan of the various cherry trees used in our area? Are there any varieties of beautyberry that are less likely to reseed? And what is a good resource book or website for identifying local weeds?
Flowering cherries typically have a functional landscape lifespan in the Southeast of about 25 years. In practice, they can live much longer but they will often go through a cycle of losing quite a few limbs, dying back and becoming unsightly without a lot of significant pruning and arborist work. For most homeowners, it is cheaper and easier to remove the tree at that point and plant a new tree.
Beautyberries are among the most attractive fruiting shrubs for the landscape. The Southeastern native, Callicarpa americana, is a large, somewhat coarse shrub that can seed around a bit in the garden. The Japanese beautyberries are much more refined, but can also reseed if they are in a suitable spot, although we really have no problem with them here at the JC Raulston Arboretum. The Mexican beautyberry, C. acuminata, is perhaps your best choice if reseeding is a serious concern, although instead of the brilliant purple fruits, you get clusters of burgundy-black fruits.
There are several weed identification resources around, but perhaps the best is the N.C. Cooperative Extension website (gardening.ces.ncsu.edu/weeds/) where you can find identification guides, management protocols and other resources. Another useful website for identifying weeds is NCSU’s Horticultural Science website (wolfpackweeds.com).
Failure to bloom
I dug up multiple irises last fall, divided the rhizomes and immediately replanted with fertilizer. Out of a total of about 20 new plants, I only had two blooms this spring. The leaves appear strong and healthy. Should I wait to see what happens next spring or dig up again and replant this fall?
Irises divided in the fall will rarely flower the following year and will instead take a season of growth to settle in and develop new rhizomes. Your plants should flower well next season. I have found that dividing crowded iris immediately after they finish flowering instead of waiting until fall will allow for enough growth that they will usually flower the following season.
Mark Weathington is the director of the JC Raulston Arboretum at N.C. State University in Raleigh. Info: jcra.ncsu.edu. Please send your garden questions, including the city where you garden, to: firstname.lastname@example.org.
Common name: Mexican Beautyberry
Botanical name: Callicarpa mexicana
Family: Mint (Lamiaceae)
Category: Deciduous shrub
Primary uses: Perennial borders, lightly shaded gardens
Dimensions: 4-6 feet tall by 4-6 feet wide
Culture: Sun to part shade
Bloom time: July to August
Bloom color: White
Hardiness: 5 degrees (USDA hardiness zone 7B)
General attributes: Mexican beautyberry is a lovely, tough shrub for full sun to part shade where it forms an upright plant with fuzzy stems and olive-green leaves. In mid- to late summer, clusters of small white flowers appear at the base of each leaf. The flowers are more attractive to pollinators than people but are nice when observed up close. In fall the real show begins with large clusters of small, round fruits which turn from pea-green to burgundy to near black. A plant in heavy fruit will arch over with the weight of the berries. Unlike the native Southeastern species, birds do not seem to like the Mexican beautyberry’s fruit, and so the display lasts well into winter. Mexican beautyberry’s stems will often die to the ground in a cold winter but will resprout the following spring.