Observations and reflections from an urban naturalist. #urbannaturalist
Natural Notes: Native Sunflowers
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September is the month of yellow, and for gardeners the easy-to-grow and popular choice of flower is the Annual Sunflower (Helianthus annuus) which adorns garden borders and roadsides across the Chicago Region. Numerous cultivars of this urban weed have been developed, and the source of commercial sunflowers and sunflower oil are derived from the Annual Sunflower (figure 1).
Figure 1: Annual Sunflower growing at the Taylor Street Farms community garden in Chicago.
But prior to European settlement, the Chicago region was largely absent of this tall and showy late-summer wildflower, whose range historically included the south-central United States into the plains and grasslands just to the east of the Rocky Mountains. Instead, the prairie landscape of Northern Illinois would have been adorned with several species of native sunflowers and sunflower-like plants (figure 2).
Figure 2: Although virtually absent of the notorious Annual Sunflower, the prairie landscape of Northern Illinois was filled with plenty of yellow blossoms.
True sunflowers are in the genus Helianthus and over 90% of species in this genus are native to North America. There are also many other species of sunflower-like plants who are primarily members of the Aster family. Let's meet some of the other sunflower species of the Prairie State as well as a few of their Aster cousins.
True Sunflowers Sawtooth Sunflower (H. grosseserratus) is common in September in suburban forest preserves as well as any remnant or restored tallgrass prairies (see figure 3 and video clip). Climbing over 12 feet into the air, this showy native sunflower attracts countless pollinators, and its roots extend several feet into the soil, allowing them to survive wildfires and mowing. Their deep roots stabilize the soil beneath, as well. Once established, Sawtooth Sunflowers can form dense clusters that can quickly fill a pollinator garden or wildflower area.
Figure 3: Sawtooth Sunflowers in bloom in the Chicago suburbs
Hairy Sunflower (H. hirsutus) is similar to Sawtooth Sunflower and grows in similar habitats, but its flower petals are more separated and it has a darker center area. The leaves are somewhat rough and "hairy". Figure 4 shows one growing in a sunny woodland edge at a suburban forest preserve not far from the Taylor Street Farms in Chicago.
Figure 4: Hairy Sunflower blooming brightly.
Who says sunflowers only grow in full sun? Woodland Sunflower (H. divaricatus) is another native sunflower, and unlike most, this one grows in semi-shady woodland areas. The flowers are a little bit smaller, but just as bright, and the leaves clasp the stem. Also, this wildflower typically blooms earlier in the year, usually late June and July, although it can also still bloom later in the season (figures 5 & 6). Woodland sunflowers are common in open woodland areas found in larger parks, gardens as well as forest preserves in the Chicago area, but are uncommon nowadays elsewhere.
Similar Wildflowers
There are also many species of bright yellow flowers that resemble sunflowers but belong to other groups of plants.
Cup Plant (Silphium perfoliatum, Figure 7) is a common prairie wildflower likely named for the cup-like area where the leaves clasp the stem (figure 8). This area holds a small amount of water, which serves as a valuable source of water for insects, birds, and other wildlife who live in dry and hot prairies. Cup plant can grow in excess of 12 feet and thrives in open, sunny areas and is drought-tolerant.
Figure 7: Cup Plant in bloom.
Figure 8: Water-filled depression where the leaves clasp the stem is a signature feature of Cup Plant
False Sunflower (Heliopsis helianthoides). Due to subtle differences in its flowering structure, this wildflower of woodland edges is quite common in gardens as well, and its bright yellow flowers that bloom in late July and August resemble those of our native sunflowers (figure 9)
Tall Coreopsis (Coreopsis tripteris) has small but numerous showy yellow flowers with a black center. This late-summer bloomer thrives in dry and sunny areas, and is often planted in prairie restoration sites. It has thinly lobed leaves and can grow close to 10 feet, though it is usually shorter. See figures 10 & 11 to admire this native prairie wildflower.
Figure 10: Tall Coreopsis growing in a prairie outside of Chicago
Figure 11: Blossoms of Tall Coreopsis
Native sunflowers and their allies attract countless pollinators and have deep roots that can protect topsoil. Planting them can help diversity our yards, gardens and communities. Native sunflowers are slower growing than Annual Sunflowers, and are slightly less tolerant of disturbance, however they are still easy to grow and they're an important component of our lost prairie ecosystems. They are also quite stunning! Perhaps next year you'll consider planting a few, such as the lovely Compass Plant shown in Figure 12?
When you think of Chicago, you probably don't think of sand dunes, prairies, or large oak trees. Yet despite Chicago being the third largest city in the United States and heavily impacted by urban sprawl and industrial blight, there remains thousands of acres of greenspace with wetlands, open woods, sandy beaches...and some rather surprising flora. The pictures below were not shot in Arizona nor in Southwest California, but were in fact taken at the 63rd street beach on a recently restored sand dune near Hyde Park in Chicago, Illinois. They are the eastern prickly pear cactus ( Opuntia humifusa ) . Figure 1: Eastern prickly pear cactus, a native plant to the Chicago region and the only native cactus to the Great Lakes area. The genus Opuntia is much more common out west where they have many different species, but in the Great Lakes and Midwest regions, the eastern prickly pear is the only native cactus. It tends to be a little bit smaller than its western counterp
Who hasn't tried pineapple before? It always seems to end up in fruit salads at family reunions, there's always someone in the crowed ordering "Hawain pizza", and the grocery stores always seem stocked full with showy pineapples displaying their rough-textured, compartmentalized skin with bizarre green leaves on top (Photo A). To most people living in temperate regions such as most of the lower 48 United States, pineapples are nothing short of exotic and unusual - and not like anything we have growing in the wild on our landscape...or do we? Photo A: A pineapple grows wild along a woodland edge in a tropical park in Ecuador, South America. Pineapples are in the family Bromeliacea, which includes a large group of mostly tropical plants that are primarily epiphytes - plants that grow on top of other plants (see photo B). Photo B: Bromiliads, shown in the center of this photo, are a common group of tropical epiphytes throughout rain forests and
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