Astragalus glycyphyllos - milk vetch

Last year I moved my 3-year old Astragalus from the main area of the Mashodack Forest Gardens into a more intensively managed As out management changed, taller volunteer groundcovers (chicory, dandelion, and some less-desired grasses) overtook and began to shade out the Astragalus.

Here are the roots! Pretty incredible.

And the whole plant layed out - I got most of the roots out, but am waiting to see if it resprouts from what was left behind.

Note: Based on my current understanding, the roots of A. glycyphyllos are not medicinal in the same way as Astragalus membranecous (Huanq qi) roots.

This is a good nitrogen fixing groundcover that we rely on heavily, but does not provide full season coverage. It also grows too tall to be grown with plants under 3'

It is a clumper that emerges from a 8-10” crown and then sends out decumbent branches up to 3’ in every direction. This does not happen overnight, and thus there is a long period in spring when surrounding areas are not covered by vegetation, leading to the potential for weed growth. Several strategies could keep the weed control up in this region around the plant – better mulching, spring ephemerals like ramps or some such, or very shade tolerant groundcovers (because this species gives very good coverage and full shade beneath for most of the season).

By chance we had some shade loving violets (species unknown, perhaps V. canadensis) growing in the periphery of an astragalus plant. Each spring we have noticed that they come back stronger than ever, though they are covered by astragalus by mid-june and don’t see sun again until the following spring. Perhaps winter annuals like mache or miners lettuce could play a similar role.

Here in our hot summers the plants sort of die back in mid summer. This is most notable in the crown/central part of the plant. There is an opportunity for a summer crop in this area, whether a summer annual or a perennial that mostly emerges at this time. Some anise hyssop started in the crown of one of our plants are and we are experimenting with letting it stay this year (note - it died). Astragalus also puts on a second flush of growth here in early fall and become quite lush again.

Also, the plant does not hug the ground closely. It starts growing somewhat upright, and the growing branches can sprawl over medium sized herbs or shrubs up to 18” high. Thus it is a bad companion for anything really less than 3’ high due to this smothering trait. If you move the branches out of the way by hand they will not return to choke anything, or they can be pruned or chop-and-dropped for mulch. Neither is what I would call low maintenance.

Perhaps this kind of observation would be true for other plants of similar habit such as Russian comfrey. We need to learn the seasonal habits of perennials, and some annuals, to fill all the seasonal availabilities in our gardens (and prevent weeds from learning of them instead).

EXPERIMENT:

Plant out a bunch of A. glycyphyllos (or use ours) and trial rings of different combinations of early spring species (violets, ramps, mache, etc.) around them, and summer species (perennials?, summer annuals) in the crown zone.

To develop a new pattern: the “seasonal Astragalus donut”.

LANGUAGE:

We need a word for clumpers that emerge from a central crown annually but take their time to get there, as opposed to clumpers that are really rooted everywhere and thus fill their space more quickly.

As mentioned below, this species leaves gaps in spring which are calling out for a spring ephemeral. Ramps are a great candidate. I have just wrapped up year one of this polyculture with a single A. glycyphyllos plant. To do this properly I would recommend A. glycyphyllos plants on 3-4' centers with ramps scattered between, perhaps with other spring species like miners lettuce, toothwort, violets, etc.

This polyculture would be appropriate in the understory of larger woody plants like shrubs perhaps jostaberry size or taller (5'+).

This is A. glycyphyllos (center) in early spring (April?) with ramps growing at the outskirts. This plant grew almost 8' across by September, in partial shade of a persimmon. It is about to engulf the ramps which were planted 18-24" out from the center of the crown. They haven't quite died back yet and will be facing too much competition for light. I'd recommend putting them a bit farther out - perhaps in a band or donut between 24" and 52" out from the crown center perhaps.

This species seems to self-seed very nicely. It is also easy to collect a lot of seed quickly form established plants.

Transplanting needs to be done with a lot of care as their taproots do not hold much soil, making for a lousy root ball. We transplant effectively in spring when leaves are just emerging to 3" or so - later and we have a lot of dieback.

After removing one, several new plants will usually grow from the broken roots which were left behind - much like comfrey and Turkish rocket (though not as bad as either!). THis suggests that it could be propagated effectively by root cuttings.