Botanical names can help pick the right hydrangea
Q: I'm new to gardening. I planted two hydrangeas from Sam's Club (not sure of the variety) yesterday, and I'm already thinking about winter care. I was reading online where you are supposed to build a cage around them with chicken wire and fill it with leaves to protect them. Is this necessary? — Rachel Chisholm, Grand Forks.
A: Hydrangeas are a well-adapted and wonderful landscape shrub, with no need for winter protection, if we choose the right types. Non-adapted types don't enjoy the same carefree existence.
Here's where the importance of botanical names shines. There are two very well-adapted species of hydrangea, along with their named cultivars, that are revealed by botanical names.
First is Hydrangea arborescens, with their large, round, usually white flower clusters and cultivars like Annabelle, Incrediball and Invincibelle Spirit. Second is Hydrangea paniculata, with pyramid-shaped flower panicles, white or pinkish colored and its cultivars like PeeGee, Vanilla Strawberry, Quickfire, Little Lime, Little Lamb, Pink Diamond, Strawberry Sundae and more.
The less-adapted species that struggles in North Dakota and upper Minnesota is Hydrangea macrophylla, and its cultivars Endless Summer, Bloomstruck, Twist 'n Shout and Blushing Bride.
So, search for the botanical name in fine print on the hydrangea label. Look for the key species Hydrangea arborescens or Hydrangea paniculata. Cultivars of those species require no extra winter protective efforts. Hydrangea macrophylla cultivars require soil amendment, a near-perfect microclimate and prefer winter protection, making them much less adapted for widespread planting.
Q: What do you think is wrong with my new Mini Twists (Pinus strobus) shrub? I planted it last summer and it looked good until this spring, when it failed rapidly. It's not dry, and I don't think it dried out late last summer with the lack of rain. It's planted on the east side of the house — is that shadiness enough to cause such a rapid decline? — Robbie Boll, Drayton, N.D.
A: Mini Twists is a very dwarf cultivar of Pinus strobus, white pine, and the needles have an interesting twisted pattern. The parent white pine is a tree-type evergreen native to the forested regions of Minnesota eastward. White pine and its cultivars aren't widely adapted to the natural prairie soils of the Red River Valley and westward, although there are a few white pines that have been successfully planted. The soil situation makes Mini Twists more susceptible to problems like winter burn, which the reddish-brown needles of your plant seem to be indicating. Had it been better adapted, the east side would be fine.
Q: Our goutweed just won't quit. Is there any way to get rid of it without poisons? — Jo Ellen Roe, Cannon Falls, Minn.
A: Goutweed is also called snow-on-the-mountain, bishop's weed, bishop's goutweed and Aegopodium. It's a good groundcover because it's tenacious, which can be both positive and negative. Without application of chemicals, control includes persistent digging over several years or smothering with mulch-covered cardboard or black plastic. Cut the goutweed back to ground level, then cover with cardboard or plastic weighed down with mulch or rock. Persistence is needed.
Q: Can a clematis plant be split in June or should we wait until fall or early spring? — Becky Bockwoldt, LaMoure, N.D.
A: The most successful time to divide a clematis is in late April or early May, just as the clematis is showing signs of new growth. Digging and dividing when a clematis is in active growth and filled with foliage carries a greater risk, requiring caution and a severe topgrowth cutback.