Dear Master Gardener,
I have never seen a Tamarix ramosissima. Someone suggested that I could use this tree close to a pathway that gets salted in the winter months.
Is this tree grown in the Toronto area? How wide would it span and how high would the lowest/highest branches be? Since it is close to a pathway I would not want it to interfere with persons using the pathway.
Tamarisk or Salt Cedar (Tamarix ramosissima) is a shrub or small tree with fine-textured foliage similar in appearance to an asparagus plant, and it has beautiful plumes of pink flowers from early to mid-summer. It grows 10 to 15 feet tall and spreads from 8 to 13 feet, but can be pruned back hard in late winter. You’re right that it is tolerant of salt. That’s the good news.
The bad news is that it is an invasive plant in many parts of North America, especially in the American southwest and the California desert. In fact it is on the Nature Conservancy of Canada’s list of “dirty dozen” weeds and identified as an invasive alien species by the Canadian Food Inspection Agency.
A native of Europe and Asia, it has migrated from gardens in the US and naturalized in the wild and is now present in most US states. It is much less widespread in Canada, but the Nature Conservancy of Canada says:
“It is known to have the potential to cause serious and irreversible damage to Canada’s native ecosystems, economy and society. This invasive alien species is an aggressive plant that requires a massive amount of water to survive. It forms a dense thicket that crowds out desirable native plant species, creates deposits of salt, reduces water tables, drains wetlands and clogs waterways with its extensive root system.”
Although it is not yet invasive in the Toronto area, it is not recommended. Here are some good salt-tolerant and low-lying alternatives to border a path: creeping yew (Juniperus horizontalis), creeping cotoneaster (Cotoneaster divaricatus) and shrubby cinquefoil (Potentilla fruticosa).
Good luck with your pathway!