Thursday, January 21, 2021

Plans for 2021

The New Year brings new opportunities for trying new things in the garden as well as continuing projects from last year. 

One project that I will be continuing from last year is removing and replacing vinca from a wooded area.   I will be expanding that to begin removing yellow archangel, Lamiastrum galeobdolon, from an adjacent area.  While this species is not currently on any official state invasive plant lists in the Mid-Atlantic, it is a species of concern.  (It is a state listed invasive in Washington State.  More locally it is on the Arlington County Virginia invasive plant list.)  It does spread aggressively by runners and root fragments.  Pulling is effective as long as all of the plant is removed.  I sprayed some of it with glyphosate last fall when doing garlic mustard treatments, but I don’t know if that will be effective.  Triclopyr is reported to be effective.

I really love the round leaflets of the trefoil and the way winds
its way along to ground, finding openings. 
 In addition to the plants added last year to replace the vinca, this year there will be some white wood aster, Eurybia divaricata, and round-leaved ticktrefoil, Desmodium rotundifolium.  Both of the species are well adapted for growing in dry, partly shady locations.  While the aster is fairly easy to come by I have been searching for the ticktrefoil ever since I first saw it in the wild back in 2005.  I’ve got a lead on it at a not-too-far-away nursery and hope to secure a few plants for this year.  The name trefoil refers to its having three leaves.  This particular species is notable for its distinctly round leaves.  An other common name is prostrate ticktrefoil, for its ground-hugging habit.  This makes a good partner in a matrix planting.  I can see using it around upright perennials like Solomon's seals and clumping ferns.

Virginia waterleaf has deeply incised leaves with whitish splotches
 that resemble water spots.  The plants shown here are in a moist
shady area near the Potomac River.  Other plants in this area include
Virginia bluebells, trilliums and bedstraw.  Photo taken early late April.

Another invasive that I have been fighting for a while and making some headway is Japanese stiltgrass, Microstegium vimineum.  I will continue fighting it with a multipronged assault, including preemergent herbicides and lots of pulling.  As I’m opening up space I’m backfilling with native species.  In addition to more of the Obedient Plant, Physostegia virginiana, that I put in last fall I‘ll be adding some Virginia waterleaf, Hydrophyllum virginianium, to a moist shady area.  This area is already populated by Virginia bluebells, Mertensia virginiana, lady fern, Athyrium filix-femina, and a variety of grasses and sedges.  (In writing this I wonder if I should look into creating a display garden of plants with only the specific epithet of virgini--.  Talk about being a plant nerd.)

The foliage on this NJ tea looks an awful lot like many Japanese spireas. 
Its compact size and tight clusters of white flowers in mid-summer
makes an excellent replacement for exotic Spireas.
While looking over the property it dawned on me that I have a number of exotic spireas that I have been ignoring, but now I’ve decided it’s time to explore some native replacements.  In the past I’ve worked on properties that have had hundreds of spirea seedlings popping up in mulched beds.  I’ve been fortunate here that I have not seen many seedlings at all.  This may be because of the half dozen plants I have all are the same cultivar, and that cultivar is less fertile.  Or the areas where the spireas are do not see much soil disturbance so seeds are less likely to get a foothold.  In any case I set about looking for a compact native shrub that grows to about 3’ and is relatively low maintenance.  Shrubby St. John’s wort, Hypericum prolificum, and the smaller cultivars of summersweet, Clethra alnifolia cv., are two candidates that I already have.  I instead am going for something new, New Jersey tea, Ceanothus americanus.  These are readily available as small plants by mail order but are not very common in larger sizes at area nurseries.  I have some seedlings on order.  Some of these I will plant out directly and some I will bring along in pots for a season.  According to Missouri Botanical Garden website, these will make good container plants that I can grow on my deck.

Prairie dropseed is notable for its dense mounds of fine foliage. 
In late summer it sends up panicles of pink-tinged flowers. 
I see it as a native alternative to exotic fountain grasses.
Another focus for this year will be to relocate the plants I have into the right place.  High on my list is to move my swamp mallow, Hibiscus moscheutos, to a sunnier location.  I put it on the edge of a swale but over the years it has gone light to heavy shade and is now barely surviving.  Another plant that I’ve allowed to get overshadowed is prairie dropseed, Sporobolus heterolepis.  This beautiful fine bladed grass can grow into 2-3’ mounds, topped by wispy flower plumes in late summer.  While primarily a plant of the Mid-West it is also found on a few sites in the East, possibly prairie remnants.  I allowed mine to get swallowed up and shaded over by some exceptionally healthy coral honeysuckle, Lonicera sempervirens.  I will be getting some new plants and put them into more open locations where they can reach full size.  These are also good candidate for container gardening, so I may set 1 or 2 aside for that purpose.

While I had planted tomatoes here, there was also a crop of black-
and brown-eyed Susans coming in.  These were all first year
rosettes so they did not compete much with the tomatoes for air-space,
but I imagine there was a lot of root competition.
In the vegetable garden I have the opposite problem.  The surrounding wildflowers, particularly the black- and brown-eyed Susans, Rudbeckia hirta and R. triloba, have invaded the beds.  Rather than throw them out I will move them to an area where I am battling Japanese stiltgrass.  The timing should work out where I can use a torch to burn off the first crop of stiltgrass seedlings at the beginning of May and then transplant in the Rudbeckias as the veggie garden is getting prepped.

Speaking of fire, last year I used the garden torch to control weeds in the vegetable garden.  Areas that were cultivated followed by flaming seemed to have fewer weeds than areas that were only cultivated.  However weeds did continue to germinate through the spring so burning is not a one-time thing.  A couple of weeks ago I went out to find a garden bed covered in hairy cress, a winter annual weed.  I got out the torch to see if I could kill these weeds without disturbing the soil.  I checked the bed about 10 days later and most of the cress was dried up.  Aside from keeping the fire under control, my biggest concern is damaging any in-ground irrigation lines.  A quick pass of a torch is enough to melt a soaker hose.   I find the use a the torch most effect at clearing areas where the fencing is buried beneath the soil.  The fire is able to reach between the holes in the chicken wire that would be otherwise inaccessible with a hoe. 

The upper image is immediately after flaming the bed on the right. 
The cress has taken on a darker green color.  10 days later most
of the cress is brown, but a few cress evaded the flame. 
Note that I pulled the soaker hose out of the bed before burning.