Naturalized is not Native

Many of you know that I love wild roadsides. Sometimes that is the best way to see some of our tough native wildflowers. But roadsides don’t get to decide what moves in, especially when humans mow them, an activity that allows non-native plant seeds to come in and get started. So while you’re admiring those roadsides, let me point out some of the flowers you might see which are naturalized, not native.

Queen Anne’s lace (Daucus carota)

The definition of naturalized is that a plant is able to reproduce and spread itself beyond where man has planted it. You are certainly familiar with some of the invasive plants that have naturalized – kudzu, privet, the white/yellow honeysuckle, mimosa trees, tree of heaven, stilt grass and others. Invasive plants go beyond the naturalized label because they outcompete native vegetation by hogging resources like light and water.

Naturalized plants are competitors for light and water, but their growth is usually not dense enough to prevent native plants from growing alongside them. Queen Anne’s lace (Daucus carota) is a good example.  While plentiful along many roadsides, the open growth habit usually allows for native plants to grow right there with it. A relative of the carrot that we eat, Queen Anne’s lace is native to Europe and parts of Asia. It spreads by seed.

Ditch lily (Hemerocallis fulva)

Another well-known naturalized plant is the ditch lily (Hemerocallis fulva). Also called tiger daylily and a bunch of other names, this plant is native to Asia. It is often found in ditches and has been eagerly transplanted to many a new home. As with many naturalized plants, it is much appreciated for its hardiness. It spreads primarily by roots.

Leucanthemum spp.

Daisies (Leucanthemum spp.) have been around so long that many folks perceive them to be native. Often called oxeye daisies, they are native to Europe and parts of Asia. They spread by roots and seed, often thriving in pastures where livestock won’t eat them or on roadsides.

Chicory - photo courtesy of Bugwood.org
Joseph M. DiTomaso, University of California - Davis

Chicory (Cichorium intybus) and batchelor’s button (Centaurea cyanus) are two blue flowers that get used in wildflower mixtures so you see them used in highway projects and as escaped plants from gardens.

Centaurea - photo courtesy of Bugwood.org
Rebekah D. Wallace, University of Georgia

Lathyrus latifolius

Perennial pea (Lathyrus latifolius) shows up occasionally. There’s a small patch near my neighborhood that returns each year.

Both vervains shown here

Brazilian vervain (Verbena brasiliensis) is becoming increasingly present. I used to only see it as I drove through middle Georgia along the highway, but now it is growing on the roadside near my house. Neighbors down the street planted the darker colored purpletop vervain (Verbena bonariensis) recently – I would be wary of that one's ability to seed around.

Rosa multiflora

Seven sisters rose, multiflora rose, Cherokee rose – we do have native roses but these are not them! The first two are probably both forms of Rosa multiflora. The first one is a double form that grows in various shades of pink while the second one (known just as “multiflora rose”) is a single form and is usually white or pale pink. The vines can get huge. Cherokee rose is Rosa laevigata, and it has a large, single bloom that is known for fragrance. These roses are native to Asia.

And you probably would not plant these, but the following plants are naturalized as well and so may be of interest when you’re trying to identify what should be removed:

Thistle is very common along roadsides and who hasn’t seen those fierce prickly leaves? You are likely seeing musk thistle (Carduus nutans). We do have some native thistles such as Cirsium altissimum which grows on the road near me; its prickles are hardly noticeable and the large leaves blow in the wind to reveal white undersides. 

Clover

Clover (Trifolium) - we do have some native clovers but this is not one of them. This is likely Trifolium pratense which is native to Europe, Asia and Africa.

Dandelion (Taraxacum officinale) – who can believe it wasn’t always here? Nope, it is native to Europe, likely brought here by colonists for their use. It is said that a single puffball (seed head) can have up to 172 seeds and those seeds can stay dormant in the soil for up to 9 years. No wonder it keeps coming back.

Photo courtesy of Bugwood.org
Dan Tenaglia, Missouriplants.com

Chinese lespedeza (Lespedeza cuneata, see picture at right) may not be a name you’d recognize, but if I showed you a big patch on the side of the road you’d say “Oh, THAT stuff!” Used for many years by federal and state agencies for bank stabilization, soil improvement, wildlife forage and cover, it is now rampant on roadsides. Learn to recognize it and remove it if you have it. If a lespedeza is what you want, there are native species and the pink-flowered Lespedeza virginica is one of them.

As pretty as these naturalized flowers may be, there is no need to bring any of them home with you. We have plenty of native plants that are much more beneficial to our local environment.

Happy Hypericums

I try to make each post as timely as possible and this one is no exception. The Hypericum plants are so happy right now. Three different species are lighting up the garden with the cheeriest of yellow flowers. I would like for more people to learn about these sun-loving, summer-blooming dynamos.

Hypericum densiflorum

The common name for Hypericum is St. John’s wort  and it is probably best known for its medicinal qualities. It appears that the non-native species H. perforatum is the one most used in that regard, so don’t come to my garden for your herbs because I don’t have that one! Some species have very showy fruit capsules and are used in floral arrangements (likely non-native also).

 

Peeling bark on H. densiflorum

In the eastern US, plants in this genus take the form of shrubs, perennials and annuals. Some of the shrubs can get quite big. In particular, bushy St. John’s wort, Hypericum densiflorum, develops a very handsome trunk that has exfoliating bark. In general, species in this genus have yellow flowers and oppositely arranged leaves that can have a blue-green tint.

Shrub form

Hypericum frondosum – this is perhaps the showiest one in the bunch. A well-known cultivar is ‘Sunburst’. This is known as golden St. John’s wort or cedarglade St. John’s wort. One gardener even found it to have great foliage color in the fall.

  

Hypericum frondosum

Hypericum densiflorum – this is one that I discovered quite by accident. It came in as a hitchhiker on some other plants and a seed found its way into the soil near the driveway. It is partially evergreen, has beautiful bark and the most flowers of any Hypericum that I’ve seen. This year’s show is probably in excess of 200 flowers. The flowers are much smaller than H. frondosum but they are perfectly stunning. 

Bumblebee approaches Hypericum densiflorum

Hypericum hypericoides – this species blooms a little later than the others and the blooms are very modest. Sometimes referred to as St. Andrews’ cross, the petals of this species do form a perfect ‘X’ shape.  I find this shrub in the wild quite often in heights that range from just a few inches to up to 2 feet tall. The taller forms are quite gangly. I wonder if they aren’t different species but have not been able to identify them as such.

Hypericum hypericoides

Perennial form

Hypericum punctatum – this is one of my favorite roadside blooms (oh wait, do I say that about everything?). Bright and cheery flowers form mostly at the top of the plant, creating a bigger effect than if they were held singly. It’s fun to get out a hand lens to see the tiny black dots that give this species its name (punctatum means “spotted).  Look carefully and see that both leaves and petals have black dots.

Hypericum punctatum

Hypericum punctatum

Annual form

Hypericum mutilum – I was quite surprised to identify a little mystery plant in my yard as this species. First of all, I had no idea that there were any annual species. Second, the whole plant was so tiny that it didn’t seem possible to be related to the others. This little guy is quite attractive in bloom.

Hypericum mutilum

Yes, the Hypericums are very happy these days. And you know what? They make me happy too!