Native Annuals revisited

The ubiquitous black-eyed Susan, Rubeckia hirta,
can bloom in its first season from seed
but may persist for up to 3 years.

A little over 10 years ago I kicked off this blog with an introduction to the idea of using native annuals in the home landscape.  I thought it was time to revisit this theme and add a little more detail with a focus on native annuals and biennials that can be used in the Mid-Atlantic garden.

While there is a growing interest in native trees, shrubs and herbaceous perennials there are very few native annuals promoted for landscape use in native landscape designs.  This lack of focus is due in large part because the longer-lived species can be counted on year after year to uphold the integrity of the design.  When included in a design, conventional annuals are often used as temporary accent pieces, just to add interest or fill a gap in the permanent landscape. 

In general, many of the annuals used in designed landscapes and home gardening are of exotic origin and have been further improved horticulturally for maximum visual affect.  These plants and methods are not bad or evil; they are just a several steps away from what would be considered natural to a given area.  While beautiful, these plants lack local character, certainly on a regional, if not continental scale.  To the extent that they are different from the local flora, they may not provide the same ecological value, such as food and shelter for wildlife in the area, as native species do. 

In contrast, native annuals may function more as perennials.  Those that are adapted to the local environment will die back after a season or two, but they will maintain a presence in the garden, by reseeding, though not necessarily in the same location.   For some people, this may be a problem since the plants will move around, disrupting the design.  Others would consider this as a natural phenomenon and appreciate how plants are able to find their proper niche.  The ideal native annual could be considered as a plant that develops quickly with more flowers, a longer flowering cycle than perennials, and that reseeds but is not invasive.

Plant Selection for the Mid-Atlantic

To generate my initial list of Mid-Atlantic annuals and biennials I used the USDA Plants database.  This database contains a listing of all plants identified as growing wild in the United States.  It does not, however, distinguish whether the plants in a location are indigenous or have escaped cultivation. Using the 'Advanced Search' function I first selected North American native species. Then I selected NJ, PA, MD, WV and VA as my Mid-Atlantic States.  For duration I selected annual and biennial and I selected 'forb' for plant type.  This resulted in a list of over 700 taxa.  This list of plant names included some duplication since varieties and sub-species are listed in addition to the species.  This database has since been revised but you can get similar results for your region using its new “Characteristics Search” feature.  Alternatively you can use the Wildflower Center’s combination plant search function on their database, but there you would be doing one state at a time.

Here are three short-lived Mid-Atlantic natives,
spotted beebalm over growing a patch of
American pennyroyal and
 backed up with black-eyed Susans.

Next, I scanned the list for species that I was familiar with that, in my opinion, had some garden value.  The attributes I considered included form, appearance of foliage or flower, scent of flower or foliage, or value to wildlife.  I came up with a list of over 40 species that I have or would like to have in my gardens.  These criteria are of course arbitrary in the sense that I am looking at features from a human perspective.  In reality each of these species has evolved to fill an ecological niche and, as such, has a real value in their natural home.  Most gardens, however, are created and curated by humans, and are not complete, natural ecosystems.  This is especially the case in urban and suburban settings where soils, water courses and wildlife corridors have been disrupted; although, we can aspire to create naturalistic areas where some semblance of a natural ecosystem can catch hold, particularly with the use of native plant species.

The Plants

Here’s a partial listing of the native annuals and biennials grouped according to their garden function.

Big Plants

Bearded beggarticks can grow from seed to about
5' tall in a season.  Bloom time is in late summer.

Despite their short life times some native annuals and particularly biennials can grow quite large, 4-6 feet tall.  These plants are best located in the background or in a larger format setting.

Bearded beggarticks (Bidens aristosa), American bellflower (Campanulastrum americanum), tall thistle (Cirsium altissimum), biennial gaura (Oenothera gaura, formerly Gaura biennis), jewelweed (Impatiens capensis), and evening primrose (Oenothera biennis).

Showy Plants

These species are of more manageable size and have good sized and/or showy flowers.

Climbing fumitory (Adlumia fungosa), partridge pea (Chamaecrista fasciculata and C. nictitans), plains coreopsis (Coreopsis tinctoria), Corydalis sempervirens, fleabanes (Erigeron annuus and E. philadelphicus), firewheel (Gaillardia pulchella), annual sunflower (Helianthus annus), cucmberleaf sunflower (Helianthus debilis), sneezeweed (Helenium amarum), standing cypress (Ipomosis rubra), spotted beebalm (Monarda punctata), sweet everlasting (Pseudognaphalium obtussifolium), black-eyed Susan (Rudbeckia hirta), clasping Venus looking glass (Triodanis perfoliata), and blue vervain (Verbena hastata).

Partridge pea returns reliably from seed
each year if open soil is available

Philadelphia fleabane is a prolific reseeder and
can grow anywhere there is an opening, such as a thin
 lawn.  Commonly grows as a biennial in my yard.

 Fillers

These plants will fill in space and while each has some interesting features, will not steal the show.

Hog peanut (Amphicarpaea bracteata), yellow corydalis (Corydalis flavula), American pennyroyal (Hedeoma pulegioides), Indian tobacco (Lobelia inflata), clearweed (Pilea pumila), red-whisker clammyweed (Polanisia dodecandra), Pennsylvania smartweed (Polygonum pensylvanicum), field pansy (Viola bicolor), and common blue violet (V. sororia).

American pennyroyal has very small flowers
but produces a strong minty scent when disturbed. 
Its tiny seeds can find their way into the smallest cracks.

Special Requirements.  

Most native annuals owe their long-term success to being adapted to some form of disturbance which makes it difficult for long-lived plants to get established.  Some species are adapted to very special conditions.  One common example is jewelweed (Impatens capensis).  This annual can grow quite large and sports distinctive orange flowers but it needs very wet soils to survive. 

Some interesting native annuals are hemiparasitic, their roots tap into nearby plants to help them develop fully.  Two examples are the False foxgloves, such as fernleaf false foxglove (Aureolaria pedicularia), which are parasitic on oaks, and Scarlet Indian paintbrush, (Castilleja coccinea), which grows with assistance from the roots of grasses. 

Winter annuals are a group of plants that have adapted their life cycles to avoid the heat and dryness of summer, or competition for sun light in a wooded setting, by doing most of their growth from fall into springtime, when light and moisture are more plentiful.

Spring blue-eyed Mary germinates in the fall and
blooms in early spring.  It is often found growing
under deciduous trees.

Some winter annuals found in the Mid-Atlantic include: Spring blue-eyed Mary, (Collinsia verna), Yellow fumewort (Corydalis flavula), Old field Toadflax (Nuttallanthus canadensis), Fernleaf phacelia (Phacelia bipinnatifida), Miami mist (Phacelia purshii), and Field pansy (Viola bicolor).

One trick with growing winter annuals is that you need to avoid pulling them out while you are cleaning up flower beds in the early spring. 

This clasping Venus looking glass came up on its
 own and bloomed in early June.  To encourage its
 return I avoided mowing the area so that it could
 set seed, but it will need open soil the following
 year so that it can grow.

A few of these species are commercially available as potted plants right now.  Others may be had by getting seed from native plant suppliers.  For others, these plants may occur naturally on your site and one just needs to be observant when they show up and then to take care that they are able to develop and set seed to create a new generation.

 

Surprise Plants

Living in a more rural area means that there is the possibility that there are still many native species lurking just out of sight.  Here are some of the plants that I have found growing spontaneously around our property.  Most of these have benefited from the removal of invasive species.  Reducing competition for light allows for germination from the seed bank and stronger growth overall.  Removing the cover, especially Japanese stiltgrass, also makes it easier to see what all is growing.  

The scalloped leaves along the stem made me think
that this was ground ivy, but the flower on top
quickly showed me to be wrong.

Among one of the first species of native annuals I tried to grow was clasping Venus looking glass, Triadonis perfoliata.  I had no luck in getting the seeds to germinate under controlled conditions (moist stratification, sterile soil, under lights, etc.)  This past spring, I came across some blooming plants as I was looking for some other seedlings in an area where I have been pulling out Japanese stiltgrass.  I can't say for sure that its emergence was due to reduction in stiltgrass, but it was much easier to find with less competition for space.  Since this species is an annual, continued success depends on it producing seed and getting that seed in contact with the soil.  Having the area less clogged with stiltgrass should help it along. 

When I first noticed it, I saw the clasping leaves on a long stem and thought it was ground ivy.  Before I could pull it I noticed the bright lavender flower at the end of the stem.  Closer examination shows that there were calyces in most of the upper leaf axils.  These had probably already bloomed out.  I will keep an eye on this area next spring to find this plant again. 

The round, glaucous stems on this bush indicated that this was some sort of raspberry. 
The berries were initially red, but all turned black over the course of a few days, so it some sort of black raspberry

When we moved here in 2012 many of the unmown areas that got any sun at all had the invasive wineberry, Rubus phoenicolasius, growing in them.  Fortunately this is not a strongly growing plant and it can be suppressed by cutting it back on a regular basis (at least once a year). It is also fairly easy to pull.  While the stems are covered with sharp bristles, these are not very stiff and will not penetrate my gardening gloves.  I was disappointed that I could not find any native raspberries (we have a ton of wild blackberries) growing in or around the woods.  In 2017 I started noticing a different berry plant showing up in various places, many of those that had been covered with wineberry.  The trifoliate leaflets and bluish blush on the rounded stems pointed toward some sort of raspberry.  (See this link to Illinois Wildflowers for way to tell raspberries and blackberry plants apart.)  It didn't matter which, as long as it wasn't wineberry (or more blackberry).  This spring these new plants flowered and produced fruit.  The berries were initially red, then turned black as they ripened.  While I have not nailed down the ID, it's a pretty good guess that these are native black raspberry, Rubus occidentalis.

I don't know if these are from an existing seed bank, or were brought in by wildlife.  Next year I will pay closer attention to the flowers to try and confirm the ID; although there are only three species of raspberries that are black, most are red.  If these came in via wildlife, they may be from some cultivated varieties rather than strictly wild.  On tasting the black berry I finally appreciate what the flavor 'black raspberry' really is like.  Jolly Ranchers have the taste right.   

Two years after I started removing the invasive species from this area,
these American germander have formed a hedge of their own.

American germander, Teucrium canadense, was one of the first native plants to emerge from what was before a dense hedge of wineberry, garlic mustard and Japanese stiltgrass.  Since this plant spreads by rhizomes and is a prolific reseeder it may be able to hold its own against the stiltgrass.  Peak bloom is in mid-summer at which time it is easily identified by the stamen arching out above the slipper-shaped, white to pale pink flower.

You can see the small white flower clusters coming
out of the stem at the bottom of this photo.

Sweet cicely, Osmorhiza claytonii, is a pretty common woodland edge native.  I usually find it along paths in partly to mostly shady wooded locations.  I usually notice it because of the deeply lobed bright green leaves and the hairs that cover the leaves and stems that catch the light.  As more invasives are removed from the understory small plants like this one are easier to spot.  Also as space opens up native like sweet cicely can fill in.

This large, about 5" long, trumpet-shaped flower is unlike most native species in our area. 
Is is actually a southwestern native but has naturalized as far north as New England.

Afterthe removal of a large pine tree I've been finding new plants cropping up all around it.  These were probably buried in the seed bank and were stirred up by the work crew or were just sitting there waiting for more light and moisture to encourage germination.  One plant that really surprised me was Sacred Datura or Angel's Trumpet, Datura wrightii.  Native to the western states, this plant is probably a garden escapee, possibly grown by the previous owner or flown in by birds. In colder climates this plant behaves as an annual though is is listed as cold hardy to USDA zone 4.

Though a little tattered Robin's Plantain seems to be
getting established in a shady portion of the lawn.

We have a number of fleabanes, Erigeron, growing here.  Most of the plants are either annual fleabane or Philadelphia fleabane, E. annuus or E. philadelphicus, respectively.  In a shady portion of the lawn (where grass doesn't grow well) I noticed a new white daisy-like flower.  It was growing up from something that looked like plantain.  While I'm not absolutely certain I'm pretty sure that this new find was Robin's Plantain, Erigeron pulchellus.  When it's in bloom I try to avoid mowing it so that it will have a chance to spread.  Since Robin's Plantain likes limy soils and has persistent green basal leaves it is a welcome addition to my natural lawn.