Knowledgebase

Native ground cover for a RainScapes erosion mitigation project #749892

Asked May 14, 2021, 10:53 AM EDT

Hello, 100 Tiarella 'Elizabeth Oliver' plants have been proposed as base plants to address an erosion problem on the left side of my house. I don't like this plant and I'm looking for a non-flowering native to replace it. Many flowering bushes and plants, as well as some grasses, have been proposed to help mitigate this erosion - I just don't want 100 flowering base plants in addition. I'd really like a conifer because, for some reason, I love conifers. if there are low-growing native conifers which are also erosion-protective, can you please name them for me - and if there are none, can give me some other green, non-flowering suggestions? Also, do you how I can reach out to the Maryland Native Plant Association by email? I can only find a P.O. Box. The landscaper I'm working with is ready to begin my project but I'm holding it up to replace the Tiarella 'Elizabeth Oliver'. So I'm looking for as many suggestions as possible as soon as possible. Thank you for any help you can offer, Liz Phillips

Montgomery County Maryland

Expert Response

Hello Liz,

There are several factors which will influence which alternatives would be the best choice - summer sunlight levels, issues with deer browsing, soil drainage (aside from the water flow causing erosion), and any limitations on mature size (height, width).

Given the landscaper's suggested plant, Tiarella, we surmise this area is wooded (or shaded by the house) and generally evenly moist - conditions Tiarella prefers. They are only in flower for two or three weeks in mid-spring. Given the desire or requirement for the project's plantings to be native, the landscaper is likely using flowering plants as they will have the greatest benefit to wildlife.

Maryland has few native conifers, especially outside of our westernmost mountains where the temperatures are cooler and soil very well-drained - preferred conditions shared by many conifers. If the site were sunny, you could use any of a handful of cultivars of ground-covering forms of Common Juniper (Juniperus communis) or the low (but not ground-hugging) forms of Eastern Redcedar (Juniperus virginiana). For part shade, Hemlock (Tsuga canadensis) is quite tolerant and has several dwarf, shrubby forms, but they are vulnerable to the serious pest Hemlock Woolly Adelgid. We are not aware of any ground-covering Hemlock cultivars, however. Similarly, other species that occur in MD (though very rarely in the wild) also prefer full sun and do not have ground-covering forms, only dwarf shrubby forms; these would be Eastern Arborvitae (Thuja occidentalis) and Atlantic Whitecedar (Chamaecyparis thyoides).

Non-conifer, non-flowering candidates are essentially limited to:

  • grasses and their cousins sedges and rushes (all of which technically do flower, but not in the stereotypically showy manner)
  • ferns
  • horsetails (Equisetum)

Horsetails and some fern species can spread aggressively if conditions appeal to them. Few ferns are evergreen, and those that are tend to be a bit disheveled-looking by spring until new growth emerges. Within grasses and sedges, a few are adapted to woodland conditions (since most grasses need sun):

  • River Oats (Chasmanthium latifolium) - they can spread aggressively as well, which while good for covering a large-scale area, may be a nuisance for nearby garden beds
  • Blue Wood Sedge (Carex glaucodea), Pennsylvania Sedge (Carex pensylvanica), and Spreading Sedge (Carex laxiculmis); though grass-like, they don't form a contiguous lawn like turf grasses do
  • Deertongue grass (Dichanthelium clandestinum)

The Contact Us page for the MD Native Plant Society lists a few email addresses - https://mdflora.org/contact_us.html


Miri

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