Sunday, July 24, 2011

Native Annuals: the Good, the Bad, and the Ugly

I have a few favorite native plants that are annuals in my area.  That means that they sprout from seed, grow, flower, set seed, and then die – all in one year.  I am also aware that there are a few plants that I don’t like that are annuals too.  So I decided to investigate a little further and see what other plants are annuals (in my area, that is – some of these plants may be considered perennial in warmer areas of Georgia).

The USDA Plants Database is a pretty handy tool when it comes to researching this concept.  Using the Advanced Search function, one can specify a list of annual plants that occur in Georgia (or any state, of course). The search generated a list that was 3 pages long!  

I have somewhat arbitrarily grouped these into the Good (the ones I like or which are interesting in general), the Bad (plants which are exceptionally weedy or aggressive), and the Ugly (those largely considered to be weeds and which have no attractive flowers).  These are my groupings alone – you may consider that items in the “ugly” should be in the “bad” or vice versa.  You may not even agree with the ones in the “good”!   I will not bore you with pictures of the ugly ones, but you can use the names provided to look them up and find pictures.

Sabatia angularis

Good:  Sabatia angularis is a soft, pink flower that blooms starting in June.  The flowers last a long time, fading to white before they go.  I find it on the partially shaded roadsides near my neighborhood, mostly in areas that escape the mower (thankfully).   

Salvia coccinea

Salvia coccinea is known as Scarlet Sage.  It has bright red flowers and will grow to be about 3 feet tall by the end of the season, branching out like a shrub as it grows.  Hummingbirds love the flowers, and goldfinches love the seeds.  It is slow to get started here: seedlings don’t usually show up until May (they sprout based on soil temperature). 

I discovered Blue curls (Trichostema dichotomum) last year when examining the sunnier roadsides.  

Dwarf St. John’s Wort (Hypericum mutilium) popped up in my yard when we cut down a big holly shrub; the petite flowers are less than a quarter of an inch wide!  

Trichostema dichotomum
Hypericum mutilium

Annual sunflower (Helianthus annuus) is naturally a well branched plant with many flowers (not one single big one, although some have been bred to do that).  Then there is Helianthus porteri, known to many as Stone Mountain Daisy.

Helianthus porteri
Photo by K. McCaustland

Jewelweed (Impatiens capensis)

Jewelweed (Impatiens capensis) is a streamside annual that many folks know as Touch-Me-Touch – the seed capsules explode when you touch them.  A similar yellow form is Impatiens pallida.

Other interesting annuals include the common purple “weed” known as Venus’s looking-glass (Triodanis perfoliata).  You may have that in your yard.  Lobelia inflata is another one known as Indian tobacco.  Perhaps the most striking annual is known as Devil’s claw, Unicorn plant or Ram’s horn: Proboscidea louisianica.

Developing seedpods of Proboscidea louisianica
Photo by M. Creekmore

Ragweed (Ambrosia artemisiifolia)

Bad: The first bad one that comes to mind is Ragweed (Ambrosia artemisiifolia).   This annual is the source of much pain to those sensitive to wind-blown pollen particles.  The greenish flowers are so nondescript that people don’t even realize it has bloomed and set seed.  Another one is Pennsylvania smartweed (Polygonum pensylvanicum) which I didn’t even realize was an annual.  I would classify this one just as annoying, especially in moist areas, but the bloom can be cute.  A common weed on the roadsides near me is American black nightshade (Solanum americanum) – not attractive, considered poisonous and downright weedy!

Ugly: Again, this is a matter of perspective! These are native, annual plants that have been basically downgraded to “weeds” in the eyes of the average person.  If you look up some of these, you will no doubt recognize them.  Bidens alba has pretty flowers, but it gets to be a giant plant and then gives off hundreds of seeds.  As with any of these, keep it from going to seed and you’ll do yourself a favor.  Lamb’s quarters (Chenopodium album) starts out small and cute and then turns into a monster.  Members of the pigweed genus (Amaranthus spp.) truly live up to their name – what ugly plants; actually pigs are cuter. 

Three-seed mercury (Acalypha virginica)

Three-seed mercury (Acalypha virginica) appears reliably every year.  And luckily, like most of these plants, it pulls out very easily.  I think these pull out easily because annuals don’t have to develop a very strong root system.  Another common weed that gives a bad name to native Geraniums is Carolina Geranium, Geranium carolinianum.  It has a very tiny flower but a huge amount of seeds.  It’s hard to convince people to appreciate the better-behaved Geraniums when they already know about this one!

Another very recognizable one is American burnweed, Erechtites hieraciifolia.  Tender, attractive foliage easily hides among other plants until the plant is about 2 feet tall.  Let it keep growing and it won’t bloom until it is about 5 feet tall!  Canadian horseweed, Conyza canadensis, has a similar habit and a similarly nondescript bloom.

Poorly drained and wet areas have their own special weeds and Canadian clearweed, Pilea pumila, is one of them.  Small, insignificant flowers (they have no petals) occur in the leaf axils and are usually mistaken for seeds – leading some people to believe it doesn’t even bloom.

So there's a quick tour of some annuals.  I hope it will give you some appreciation for the "good" ones and some perspective on the others. The thing about annuals: if you don’t like them, they only live one year.  If you like them, unfortunately they only live one year!  Either way, you can depend on them to set a LOT of seed, so act accordingly.


  1. Hi Ellen,
    We have quite a bit of the three seed mercury in MN. I see the leaves have been munched by some insect, perhaps a caterpillar. I usually pull it out but now I'm curious if it's a host plant for some type of lepidopteran?
    Great post.

  2. Do you grow Devil’s claw?
    I've been fascinated in reading about that plant... It apparently kills animals?
    In my reading, I've discovered some beautiful pictures of it's flowers, and am of mixed feelings about the appropriateness of bringing that interesting plant anywhere that it might become a problem.
    So... I'm curious what information you could provide re your personal experiences with Proboscidea.

  3. I don't grow it myself, but a friend of mine does. I had not heard of any toxicity with it.