Sunday, June 3, 2012

Roadside Plants in June

There is a time and place for everything when it comes to blooms on plants.  The early summer roadside is mostly green but there are a few blooms worthy of discussing either because they are good things or because they are bad things.  These are blooms that I see driving around in North Georgia.  It takes special plants to withstand roadside conditions that are usually exposed, hot, and often dry but sometimes wet depending on the drainage.  And it takes an educated eye to be able to recognize some of these at 45-55 miles per hour!

Trumpet creeper (Campsis radicans)

One of the most eye catching blooms is a vine that peeks out from inside of shrubs, scrambles up trees and makes use of whatever utility poles it can find. Trumpet creeper (Campsis radicans) is a bit aggressive in the garden but a delight on the roadside.  Hummingbirds love it of course.

This picture looks orange, but it really can be quite red when you see it in person. There are orange and yellow cultivars that you can buy.

White flowers blooming now include elderberry (Sambucus nigra ssp. canadensis), a big shrub that loves moist roadsides. The flowers are rather flat in appearance and can be as large as a dinner plate. The flowers will turn to clusters of purple berries in time.

Sambucus nigra ssp. canadensis

Frequently seen is the naturalized Queen Anne’s lace (Daucus carota), a non-native perennial with flowers that are whiter than elderberry’s more cream-colored flowers and have a more domed shape.  I get briefly excited when I see it on the roadside, thinking it might be elderberry, only to be disappointed when I realize it is not.

Queen Anne’s lace
Chris Evans, River to River CWMA,

Another white flower blooming in abundance is eastern daisy fleabane (Erigeron annuus). This annual flower has up to 20 small flowers per plant, creating a delightful display when there are hundreds of them together. It provides valuable nectar for small native bees, flies and small butterflies.

Erigeron annuus
There is nothing like a bright orange plant to catch your attention as you pass at a high rate of speed. I remember the first time I saw orange butterfly milkweed (Asclepias tuberosa) – it was like “Whoa! What is that?”. Now I look for about this time every year.  I’m always excited to spot more of it in the wild because I know it is important for monarch butterflies.  Often the flash of orange that I see is not milkweed. More common now is the naturalized orange daylily (Hemerocallis fulva) that blooms at the same time. This non-native lily decorates ditches and sunny roadsides in May and June.

Charles T. Bryson, USDA Agricultural Research Service,

Pink flowers are well represented this time of year. The pink blooming tree that is – alas – so common in Georgia is actually non-native but has been with us since 1745 when it was brought over from China. It is usually called mimosa tree but is also known as silk tree; the scientific name is Albizia julibrissin

Mimosa microphylla

I suppose the common name “mimosa” is due to its resemblance to a group of perennials in the genus Mimosa. I noticed one blooming on the roadside where I walk this week. The tiny blobs of pink fluff were arranged on a prickly vine-like plant whose foliage contracted upon contact; it’s common name is “sensitive” plant.  I think the one I found is Mimosa microphylla.
Phlox paniculata

Other pink perennials you might see are the tall pink phlox (Phlox paniculata), non-native pink cosmos (Cosmos bipinnatus) in the median strips when DOT plants wildflower seed mixes, and of course thistles.  Thistles are an often overlooked plant, usually scorned for their prickly foliage. There are native ones and non-native ones – I found this non-native Carduus nutans yesterday while photographing something else. In the fall I find the native Cirsium altissimum blooming; it’s prickles are a lot softer!

Carduus nutans

Blackberries can look like pink flowers from a distance

Blackberries have formed bright clusters of pink berries that might appear to be red flowers when you’re whizzing by them in the car. I snapped pictures of what I believe is Rubus argutus on the roadside near me. Give them time and they will turn from pink to red to black.

Two confusing plants are sumac (Rhus spp.)  and tree of heaven (Ailanthus altissima). While they have similar looking compound leaves, they are really very different. Tree of heaven has long finished blooming while sumac is blooming now. Sumac is considered a shrub while tree of heaven can grow 20-50 feet tall.  The bright orange seed heads forming on female Ailanthus altissima can make it appear that they are blooming. Sumac shrubs will have conical upright flower clusters that transition to clusters of red berries over the summer.

Seeds on female Ailanthus altissima
Flowers on staghorn sumac,  Rhus typhina

Besides dandelions and dandelion-like hawkweeds (Hieracium spp.), the only yellow flowers I have seen are black-eyed susans (Rudbeckia hirta) and whorled coreopsis (Coreopsis major). We will see many more yellow flowers soon enough.

Rudbeckia hirta
Coreopsis major


  1. Once again, a great post.. Tree of Heaven is invasive on Long Island.. Not sure of it's status elsewhere..

  2. We have many of the same native plants here in Michigan though we are a few weeks behind you. Blooms are at their height in July here.

  3. Cindy, Tree of Heaven is invasive just about everywhere it gets a foothold. Every time I mention "that purple tree" as being invasive, the response I get is something like, "But it's so pretty!" I obviously have a failure to communicate!

    Ellen, I love that you included the invasives/naturalized plants in this post to help people identify the difference. Kudos! -- Becky

  4. So...just how aggressive is campsis radicans in the garden?

    I've thought about adding either trumpet creeper or crossvine (bignonia capreolata) in my garden, but I'm worried that once the barn door is unlatched I won't be able to get the vine back in!

    Also would you say that all non-natives should be shunned? I'm rather fond of cosmos bipinnatus and it doesn't seem like a bully. The bees and butterflies and gold finches seem to like it too...

  5. El, I keep seeing flashes of orange along the roadside and milkweed alert goes off in my head. Have not seen a single blooming stick of milkweed...always daylillies:(

  6. Jeff - you and I are united in disappointment, I guess!

    Aaron - Campsis will be most aggressive in "ideal" garden conditions: good, moist soil, using fertilizer, regular watering, sunny, etc. Crossvine is less aggressive, I think. I don't shun all non-natives myself - favorites like gardenia and tea olive are two that I have in my own garden. I think it is something that each of us has to decide for ourselves and the "bully" aspect of the plant needs to be considered as you said. I do love those pink cosmos too.

  7. When does sumac bloom in northwest Ga?