Savanna Species
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Bur Oak is a member of the ‘white’ oak group. It is the most common and widespread oak in the state and the dominant species in the oak savannas of Minnesota.
A mature tree can be very large – they can grow up to 100 feet tall and 75 feet wide. They can live for over 300 years.
The leaves are also very large – up to 12” in length. They are dark green and glossy on the top and grayer on the underside. The leaves have many rounded lobes and the indentation between the lobes can be very deep, especially near the center of each leaf. Fall color is a dull yellow.
The bark is typically dark grayish brown, rough, and deeply ridged. It is very thick, which protects the tree from wildfires.
The acorn is the largest of all native oaks and can get up to 1.5”. The cup that encases the acorn can cover over half the fruit and is fringed with thick course hairs that are the basis of the name ‘Bur’.
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A short, warm season grass that grows 2-3 feet tall.
The leaves are rather wide, stiff, and coarse. They are bright blue-green color, until fall, when the entire plant fades to a reddish tan color.
Side Oats Grama Grass is one of the few native grasses to have an attractive flower. When the plant blooms in mid to late summer, the seed heads have reddish-purple anthers that dangle below, and white, fuzzy hairs above.
An easy way to identify this grass is by the seed heads: all seeds appear to come from one side of the stem. When the seed heads dry, they have a distinctly oat-like appearance.
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Spiderwort is a medium height perennial wildflower that can handle the sandy, dry soils of the oak savanna. It typically gets 2-3 feet tall.
The blooms emerge in May and last through June. They are typically blue or deep violet-blue but can occasionally be pink or white. The flowers each have exactly 3 petals, and will often open in the morning, then close in the heat of the afternoon
The blue flowers were used by Native Americans as a dye.
Spiderwort can spread by both runner roots and seed. Because they spread easily, they often create large colonies that, when in bloom, create a striking landscape.
The foliage is long and leafy with a gray-green color. It resembles that of a daylily, but a bit thinner.
When the stem or leaves are broken, they emit a fluid that hardens into a cobweb like structure.
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American hazelnut is one of the few shrub species native to the oak savanna.
It is a large, densely branched shrub that can grow up to 15 feet tall and wide. It can often form large thickets because it spreads by sending up new shoots from spreading underground roots.
It produces edible nuts that ripen in mid-August into September. The nuts are small and are enclosed by leaflike bracts.
The leaves are oval and sometimes slightly heart shaped, with serrated edges and can be wavy. In the fall, the leaves turn beautiful shades of reds, oranges, and yellows.
2-4” long flower spikes, called a catkins, are formed in fall, then remain on the plant until the following spring when they open up. The catkins are an important food source for wildlife through the winter.
In early April into May, the shrub has very small flowers that resemble buds. The only bit of color are the tiny red styles, which look like thin red threads.
Another way to identify the American Hazelnut is by the mix of soft, white hairs and bristly glandular hairs on both the leaf stalks and the new twigs.
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Indian Grass is a warm season grass that can grow up to 7 feet tall. It is one of the earliest warm season grasses to form seeds.
It has a more graceful, fountain-like habit.
The seed heads develop in late summer. When they first emerge, they are tight spikes of bronze, but as they mature, they open to a large plum of light rusty yellow color. The seed heads are typically upright or slightly arched.
The leaves are rough and turn yellow in the fall.
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Wild Bergamot, which is often referred to as bee balm or Monarda, is a classic prairie and savanna plant that grows up to 4 feet tall.
It spreads easily through its runner roots and will often form large masses which are very easily spotted when in bloom.
Blooms appear in mid-summer and can last until early fall. The tubular flowers range in color from violet, lavender, and pink. The blossoms look like pom-poms or little firework displays.
Because it is part of the mint family, the entire plant is very aromatic, smelling very minty especially when rubbed or crushed.
Like all members of the mint family, the stems of the plant are square and typically hairy. The leaves are light green, coarsely toothed, and are slightly hairy on the underside.
The leaves of the plant have been used to flavor tea, and Native Americans used the plant to treat a wide variety of illnesses and injuries.
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June Grass is a cool season grass and is one of the first grasses to green up in the spring.
It is a short grass, only getting about 2 feet tall.
The blue green leaves are narrow, very vertical, and tightly bunched, giving the grass a tufted appearance.
The seed heads show up in early to mid-summer and look like plumes of dense spikes that are silvery-green to purplish in color when they first emerge, fading to a tan as they mature. Seeds are produced through September.
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Prairie Dropseed is a shorter, warm season grass that really takes off in the heat of summer. It typically reaches 2 feet tall, with the seed heads standing closer to 3 feet tall.
The form of this grass is unique and makes it easy to identify. It forms dense tufts of gracefully weeping leaves, with the seed heads standing upright, slightly arched above the leaves.
Another distinguishing factor of Prairie Dropseed is that it is one of the few grasses that is fragrant. When in bloom, the seed heads give off a unique smell, often compared to buttered popcorn.
Seed heads develop in late summer through fall and are airy and have pink and brown tints.
The leaves are thin, fine textured, and lime green. They turn a beautiful golden with orange tones in the fall.
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Big Bluestem is a warm season grass, meaning that the soil must warm up before it will start to grow.
Big Bluestem is an important and iconic plant of both the tall grass prairie and oak savanna.
It can grow up to 6-8’ tall, and well-established plants can grow roots 7-8 feet deep, meaning it is very drought tolerant.
Seed heads show up in late summer. Usually there are 2 or 3 spikes that attach at a common joint of the stalk, resembling a turkey foot.
The stem is blueish – purplish at the base and covered with long, fine hairs on the leaf blade.
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Pasque Flower is one of the first wildflowers to bloom in the spring. It typically emerges while there is still snow on the ground and can bloom as early as the first week of April.
The open bell-shaped flowers can be as large as 2” across, and range in color from white to blue-violet. Individual flowers are held by leafless, hairy stems. As the plant blooms, the leaves begin forming.
The flowers are followed by silvery, feathery plume-like seed heads.
Pasque Flower has deeply cut, silky, hairy, fern-like foliage that remain well into summer. The hairs on the leaves help insulate the plant in the cold.
It is a small plant, only getting about 8” tall and wide.
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This late blooming perennial can grow up to 5’ tall and is an important late season food source for a wide variety of pollinators, including the monarch butterfly. •
Blooms appear in August and last through October, occasionally even lasting into November. The flowers have purple petals with bright orange-yellow centers. The profuse blooms show up at the tips of the leafy branches.
New England Aster is easy to identify, even without the beautiful blossoms, by the stems and leaves which are both hairy. The leaves are arranged densely around the strong stem, nearly encircling it. The lower leaves often dry up and turn brown when the plant is in bloom. The stem turns brown to reddish late in the season.
This tall aster has a unique form as it can be long and leggy, drooping over on surrounding plantings when in bloom.
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This perennial wildflower thrives in even the sandiest of soils like those of the oak savanna in Bunker Hills Regional Park. Mature plants can grow 2 feet tall and form clumps up to 3 feet wide.
Clusters of stiff, leafy, light green stems often originate from one taproot. The stems are densely covered in short, bristly hairs. •
The leaves are long, skinny, and lime green. Like the stem, they are covered with short stiff hairs on both sides, which make the plant feel rough.
Tubular blooms cover the tops of the plant starting in late May and can last into July. They are deep yellow, have 5 lobes, and form at the end of each stem.
The seeds that take the place of the flowers are white and stone-like.
Native Americans extracted a reddish-purple dye from the root. They also used the root for various medicinal purposes.
