Garden plants – Discover-Nature

American Asters

As we enter early autumn, it is late in the growing season for the central United States, and many insect species are still actively looking for pollen and nectar as they get ready for winter. Migrating birds and species that overwinter here are also seeking daily meals. Fall flowering plant species are much fewer in number than summer blooming species, but include varieties of American asters, Symphyotrichum spp.; goldenrod, Solidago spp.; black-eyed Susans, Rudbeckia spp.; coneflower, Echinacea spp.; sedum, Sedum spp.; and anise hyssop, Agastache spp.

^{American Aster by Andrew McKinlay, Aug 2013; Anise hyssop by Steve Guttman, Oct 2011; Black-eyed Susan by Jodi Grundig, Aug 2009; Coneflower by Bonnie Leer, Jul 2008; Goldenrod by Cathy Baird, Aug 2013; Sedum by Eleanor Martin, Jul 2009}

In this blog, we take a look at American asters, which make up a genus of over 100 species of perennial plants, all of which are native to North America. Asters like full or partial sun and reach heights of between one and six feet. They display a variety of colors from white to blue to purple. They do best in wet soils. Asters are often grown in pots or used in borders, as well as being found in a variety of wild habitats including forests, savannas, prairies, and wetlands.

^{American painted lady on Pacific aster by TJ Gehling, Oct 2023; Gulf fritillary on white aster by Vicki DeLoach, Ot 2012; Leaf cutter bee, Megachile spp, on New England aster, by GreenRavenPhotography, Sep 2016; Metallic green bee on white aster by Jacqui Trump, Oct 2021; Pecks skipper, Polites peckius, on smooth blue aster, Symphyotrichum laeve, by Tom Potterfield, Sep 2016}

These asters are an excellent source of nectar and pollen sought by both long-tongued and short-tongued bees, butterflies, wasps, and beetles. All parts of the plant are edible, although some species may contain mild toxins, making the animal eating it ill. Leaves and stems are eaten by grouse, turkey, chipmunks, mice, and deer. The abundant seeds are available long after most other flower seeds have been consumed or buried. Large quantities of seeds are eaten by migrating bird species including dark-eyed junco, Junco hyemalis; indigo bunting, Passerina cyanea; American tree sparrow, Spizelloides arborea; and American goldfinch, Spinus tristis.

^{American goldfinch, Spinus tristis, by F Delventhal, Jul 2022; American tree sparrow, Spizelloides arborea, by Tom Benson, Nov 2018; Dark-eyed junco, Junco hyemalis, by Stan Lupo, Mat 2020; Indigo bunting, Passerina cyanea, by Mitchell McConnell, Apr 2013}

Asters are sometimes referred to as a keystone species. Keystone species can be either plants or animals that are essential to maintaining the health and functions of the entire ecosystem to which they belong. The introduction or loss of a keystone species may significantly affect an entire ecosystem in either positive or negative ways. Populations of other organisms may be altered, habitat changes can be observed, and biodiversity can rapidly change. American asters, along with the other late blooming flower species, are an important food source late in the growing season for maintaining a healthy population of pollinators, migrating birds, and over-wintering wildlife.

To learn more about seasonal changes and how our native species are adapted to handle these conditions, consider a visit to the Jurica-Suchy Nature Museum or a nature center near you.

Buttonbush

Over the past several days, there has been a lot of activity in our backyard pollinator garden in the area surrounding the buttonbush, Cephalanthus occidentalis. This native shrub is a multi-stemmed flowering species that can grow from 3′ to more than 12′ tall. It needs lots of sunshine and prefers moist soils. Found in many habitats including sub-tropical swamps, shrub swamps in the northeast and upper Midwest, and southern and northern floodplain forests east of the Mississippi, this species prefers swampy backwater areas, marshes, wet meadow and bogs.

^{Buttonbush, Cephalanthus occidentalis, whorled leaves by loonyhiker, Oct 2010}

Newer stems are green, but quickly turn dark brown to almost black, becoming scaly with age. Leaves are opposite or whorled around the stem, each one protruding at a slightly different angle than the one above. It is thought that this arrangement provides maximum exposure of the plant’s total leaf surface to the sun.

^{Buttonbush flowers by DonArnold, Jul 2023}

^{Bumblebee on buttonbush by DonArnold, Jul 2023}

The flower clusters appear as small balls between 1/2″ and 1″ in diameter, with over 200 spikes poking outward covering their entire surface. Each spike is actually an individual flower. Flowers are closely grouped together and exude an intense, sweet fragrance. The plant reproduces through a two-stage cycle where pollen is produced and falls onto the immature pistil. As visiting insects brush through the closely grouped flowers, pollen rubs off onto their bodies. Once the pollen is gone, the pistil matures and becomes sticky at the end. As other insects arrive, pollen from other plants is picked up by the sticky end to pollinate the plant.

After pollination is complete, and the flowers drop off the plant, the ball-shaped seedhead turns completely brown. Unless it is brushed off by a passing animal or it is eaten, the seedhead may remain with the plant through the entire winter season, dropping off in spring. Seeds will often disperse into wetland areas, floating to shore. Each seed ball contains two nutlets.

^{Red Admiral butterfly on buttonbush by DonArnold, Jul 2023; Honney bee on buttonbush by DonArnold, Jul 2023; Long-tongued tiger swallowtail on buttonbush by Owen Sholes, Getty Images}

Pollinators include many long-tongued insect species especially bumblebees, honey bees, tiger swallowtail butterflies and black swallowtail butterflies. In addition, over two dozen bird species utilize the shrub for food, shelter, and nest building material – most notably are wood ducks that use the plant’s structure to shelter their young. Amphibians and reptiles hide among clusters of buttonbush in wetland areas for protection during the breeding season. Several honey-producing bee species are attracted to its pollen and nectar.

^{Buttonbush, Cephalanthus occidentalis, by NC Wetlands, Aug 2018}

With more than a dozen buttonbush species worldwide, it is an easy plant find and get close to for observing its flowers and fruits, as well as the behaviors of the many animal species that frequent this shrub.

Succulents

Plants that save water!

Succulents are a group of plants able to store water in their leaves, stems, and roots. This group includes between 8,000 and 10,000 species across several plant families, equal to 3%-5% of all plant species. They are found on every continent except Antarctica.

Backyard succulent garden by DonArnold, 2022

Succulents are largely perennial species storing water for use in drought periods. They have features that limit the amount of water loss from evaporation. Most species have thick cuticles, the outer skin, and fewer stomata, the cells on the underside of leaves used for exchanging gases, including carbon dioxide and oxygen, with the outside environment. Many plants exchange gases during non-daylight hours only.

By storing water, succulents are able to survive in habitats with limited water availability, including habitats that receive only dew or mist versus measurable rainfall. Limited water availability may also refer to habitats where infrequent rainfall occurs with lengthy intervening dry periods.

Aloe vera crosscut leaf by Evelyn Chu, Dec 2010

Additional water-saving features include round versus flat leaves and stems exposing less surface area to the air and thus reducing water loss through evaporation. Plant surfaces may be waxy, hairy, or spiny creating micro-habitats to further reduce air movement across the surface. Plants are able to seal and heal wounds quickly. Roots are shallow allowing the plant to absorb minute amounts of moisture reaching the soil.

Hydrangea leaf, flat leaf structure with large surface area, by DonArnold, 2022

Plants retaining large amounts of water must have robust support to handle the extra weight. In smaller plants, additional fiber strengthens stems and leaves. In larger plants, such as trees and shrubs, stems contain thicker wood walls to maintain their upright stature. This provides additional protection against wind damage. In most species, if any part of the plant is broken off, fragments are capable of taking root and growing a new plant.

Since water temperature does not fluctuate as rapidly as air temperature, succulents are able to stay warmer due to the large amount of retained water. Succulents are still vulnerable to damage at very low freezing temperatures, but only over a prolonged period of several hours.

Succulents are often found in homes and backyard gardens and are well-liked because of their low maintenance and unusual appearance. Popular varieties that may come to mind include aloe vera, Christmas cactus, jade plant, sedum, and yucca. Consider starting a small pot on your windowsill or planting some in your backyard. Note: Be sure to pay close attention to the labels identifying which can be grown outdoors in your area.

Aloe vera by Forest & Kim Starr, Dec 2015

Jade plant, Crassula argentea by Hornbeam Arts, Nov 2012

Pollinator Garden

Our pollinator garden is filling in rapidly with the warmer temperatures and ample amounts of rain we are experiencing. Many species in our area, including bees, wasps, flies, ants and hummingbirds are pollinators providing plant species with the essential service of moving pollen from one flower to another for fertilization. Many popular native species are found in our garden; let’s take a look at a few of the ones now in bloom.

Golden Alexanders, *Zizia aurea* by DonArnold

Mining Bee on Golden Alexander, © Heather Holm, 2015.

Golden Alexanders, Zizia aurea, is found in a variety of natural environments from open woodlands to prairies to fens. This member of the parsley family is visited by Pearl Crescent butterflies, Phyciodes tharos, and Spotted Thyris moths, Thyris maculata, especially where these insects find other food species including Clematis and Houstonia. Mining bees, small in size and emerging in early spring, are the primary pollinator, picking up pollen on the hairs of their upper legs as they feed on the flowers.

Virginia Waterleaf, *Hydrophyllum virginiatum* by DonArnold

Another favorite pollen source for bees is Virginia Waterleaf, Hydrophyllum virginianum. With its white to pale violet flowers and leaves that look like they are stained from water; this plant’s nectar also attracts the Red Admiral butterfly, Vanessa atalanta, and a few species of beetles. The stamens on this flower extend well past the petals making it difficult for small, short-tongued insects to get close enough to the flower tube to obtain nectar. Bumble bees, one of the primary pollinators feeding on the nectar, use their larger bodies to push past the stamens picking up pollen to transfer from one flower to another.

Woodland phlox, *Phlox divaricata* by Joshua Mayer, 2010

Woodland Phlox, Phlox divaricata, also known as Wild Blue Phlox, is often found in open woodlands. This flower is attractive for pollinator gardens due to its blue flowers and good growth in partially shaded areas. Pollinators include many butterfly and moth species with long tongues that can reach deep into the long flower tube for the nectar at the base. As the butterfly feeds, its proboscis (tongue) contacts the stamens to pick up pollen which is transferred to the next flower.

Jacob’s Ladder, *Ploemonium reptans* by DonArnold

Another flower in the blue spectrum is Jacob’s Ladder, Polemonium reptans. This species does well in partial shade or a moist area in full sun. The flowers are visited by bees, flies and beetles. Large bees are the best pollinators as they collect pollen on their heads and thoraxes when pushing through the stamens to get to the nectar at the base of the petals. Previously collected pollen brushes off on subsequently visited flowers.