Download Resource - The Stewardship Network

MISTAKEN IDENTITY?
Invasive Plants and their Native Analogues
An Identification Guide for Ives Road Fen Preserve
While some invasive plants are distinctive and easily recognized, many others are difficult to distinguish from one or more species of our native
flora. The result can be elimination of native plants that we want to preserve. This guide presents a side by side photographic comparison of the
key characters helpful in confirming identification to allow you to quickly narrow down the possibilities. It covers invasive species at Ives Road Fen
Preserve south of Tecumseh, Michigan but would have some applicability to other preserves in Michigan and Ohio.
Each page has one invasive species and one or two similar native species. Photographs show key differences in such features as leaves, stem, fruit
and flower. In some cases you get a bonus, such as a butterfly, with the photo. Bloom time and location information is given verbally. The remarks
below the table discuss related invasives that are easy to distinguish. There are many more alien and invasive species not in this guide but most of
them are easy to distinguish.
Invasive
Glossy Buckthorn (Frangula alnus)
Thin,
shiny
leaves
with entire
(not
toothed)
margins.
Leaves
Bark
Native
Spicebush (Lindera benzoin)
Location Wetland only
Bloom
June
start
Light green,
dull and have
rounded
teeth. The
plant only gets
a few feet tall
and grows in
clumps.
Alternat
e,
simple
light
green
leaves.
Buckthorn
lenticels
are longer
horizontally
than
Spicebush.
Buckthorn
bark is
grayer than
the brownish Spicebush bark.
Wood
Native
Alderleaf Buckthorn (Rhamnus alnifolia)
Spicebush lenticels tend
to be smaller and
rounder than the
buckthorn lenticels. The
bark is a little browner
than buckthorn bark.
Buckthorn wood is
orange-yellow
when cut.
The bark
is dark
brown
with no
white
lenticels.
Spicebush wood
is white with a
slight greenish
tinge. If you
accidentally cut
it, don’t treat the
stump and it will
grow back.
Wetland only
April
The wood has a
slight yellowish
tinge.
Wetland only
June
Invasive
Narrowleaf Cattail (Typha augustifolia)
Leaves
Native
Common Cattail (Typha latifolia)
Leaves are up to ½” wide.
Up to 1” wide.
Flowers
Location
Bloom
The male flower containing the
pollen (top part) and the female
flower (bottom part) have no gap
between them. By the end of the
season the part of the stalk where
the male flower was will be bare.
Wetland
June
Wetland
June
Invasive
Hairy Willow-herb (Epilobium hirsutum)
Leaves
Stem
The
leaves are
sessile
(directly
attached
to the stem) and up to 1” wide.
Native
Fen Willow-herb (Epilobium
leptophyllum)
The leaves are less
than ¼” wide.
The stem has opposite
leaves and is up to 6.5
feet tall.
Northern Willow Herb (Epilobium
ciliatum)
The leaves are up to ½” wide.
The stem has alternate leaves and
is up to 5 feet tall.
The stem is up to 3 feet tall.
Flowers
The showy rose-purple flowers
extend from leaf axils near the
top of the plant. Flowers are
approximately ¾ inch across.
Location Wetland
Bloom
July
The white or pink flower
with a long calyx tube is
about 1/3" across.
The white or
pink flower
with a long
calyx tube is
1/6” to 1/3"
across.
Wetland
Wetland
July
July
In the preserve there is another invasive willow-herb which resembles Hairy Willow-herb except with slightly smaller flowers. There is another native willowherb which resembles Northern Willow-herb.
Summary: Native willow-herbs have tiny flowers.
Invasive
Purple Loosestrife (Lythrum salicaria)
Leaves
Native
Common Hedge Nettle (Stachys
tenuifolium)
The leaves are
opposite and
entire (smooth
edges)
The
Leaves
are
opposi
te and
toothed.
Stem
The square stem
is purple or green
with opposite
leaves and is up to
7 feet tall.
Flowers
The flowers are in
thick purple spikelike inflorescences.
All petals are the
same shape.
Location Wetland
Bloom
July
Native
Purple-Fringed Orchid (Plantanthera
psycodes)
There are 2-5
leaves sheathing
the stem,
gradually
reduced to bracts
higher up on the
stem.
The round stem is up to 2 feet tall.
The square stem
has purple blotches
with opposite leaves
and is up to 4 feet
tall.
The flower spike is 1-1 ½” in
diameter. The flowers are
about ¾” long. The lower
petal forms a lip.
The rose-purple flowers form
an interrupted spike. The
lower petal forms a lip.
Wetland
Wetland
July
July
It isn’t hard to distinguish purple loosestrife but sometimes when we are spraying acres of it we develop a conditioned response to pull the trigger on every spike
of purple flowers we see, especially if all we have seen for the last 30 minutes is Purple Loosestrife. Be sure before you spray. Think twice before turning loose an
AmeriCorps crew with backpack sprayers.
Summary: Purple Loosestrife is tall and has a thick inflorescence with all flower petals having the same shape.
Invasive
Musk or Nodding Thistle (Carduus nutans)
Rosette
Stem
Native
Swamp Thistle (Cirsium muticum)
Smooth,
not so
deeply
cut, with
a white
tinge on
the ends
of the
lobes.
Very
spiny.
The
purple
flower is
1 ½ -2”
high.
The
heads
nod.
Location Upland and occasionally wetland
Bloom
June
start
Native
Field Thistle (Cirsium discolor)
The leaves are
deeply cut and
usually have a
reddish tinge.
The rosette leaves
are deeply cut and
have many spines.
The stem is smooth. It
is usually purple but
sometimes green.
Flower
The stem
leaves are
loose, not very
spiny, almost
soft looking.
The purple
flower is
1 ½ -2” high
and
upright.
Wetland only
July
The
pale
purple
flowers
are 1 ½
-2”
high
Upland only
July
Bull Thistle (Cirsium vulgare), another invasive, is similar to Nodding Thistle except that it has upright flowers. The other thistle you are likely to encounter,
Canada Thistle (Cirsium arvense), is also invasive. It is shorter, more slender and has lighter colored flower heads than the three species above.
Summary: Native thistles are less spiny and bloom a month later than the invasive thistles. Rosettes are harder to tell apart until you have some practice.
Invasive
Multiflora Rose (Rosa multiflora)
Leaves
Usually 7-9
leaflets, fringed
stipules.
Native
Prairie Rose (Rosa setigera)
Native
Swamp Rose (Rosa palustris)
The leaf has 5-9
leaflets and a
long narrow
stipule with
revolute (rolled
back) margins.
Five leaflets
on nonflowering
stems, three
on flowering
stems,
smooth
stipules.
Prickles
Flower
Prairie Rose has
numerous white prickles
near the bottom of the
stem. They are stout
and recurved, similar to
Multiflora Rose.
The prickles are numerous, stout and
recurved. Older ones at the base of the
stem are dark.
Many white
flowers about
1“ wide.
Location Upland and wetland
Bloom
June
start
The lower stem has a few
straight, slender prickles.
The ends of the branches
have none.
Clusters of a few
pink flowers
about 2 ½ “ wide.
Upland and Wetland
July
Clusters of a few
pink flowers
about 2” wide.
There is a wide,
flat pistil in the
center of the
flower.
Wetland only
July
The other native rose on the preserve is Carolina Rose (Rosa carolina). It is short and usually on the edge of the woods. The other non-native is Sweetbriar (Rosa
rubinigosa). It has pink flowers, grows in the upland areas and has very many prickles. There are only a few of them on the preserve. Multiflora Rose is being
killed off naturally by rose rosette disease. It kills most of them in the upland and fen but is slow to reach some of the ones in the woods.
Summary: Native roses have large, pink flowers, smooth stipules and bloom a month later than Multiflora Rose.
Invasive
Hairy Vetch (Vicia villosa)
Leaves
Stipules
7-12
pairs of
leaflets
and a
terminal tendril that clings to
adjacent vegetation for support.
Native
American Vetch (Vicia americana)
4-8 pairs
of
oblong
leaflets
and a
terminal
tendril.
Stipules ¼” or less
long.
Flower
, one-sided racemes.
Location Upland sunny
Bloom
June-July
Native
Marsh Vetchling (Lathyrus palustris)
Three pairs of
leaflets and
terminal
tendrils.
Stipules sharply
toothed.
5-20
pairs
of
violet
blue
flowe
rs, ½“
long,
in
dense
Stipules half-arrow
shaped.
Bluish-purple
flowers, ½ - ¾“
long, in a loose,
few-flowered
raceme.
Upland edge of woods
June
2-9 pink or bluishpurple flowers, ½
- ¾“ long in a
long-stalked
cluster.
Wetland only
June
The other native vetch on the preserve is Carolina Vetch (Vicia caroliniana). The flowers are white or white with a bluish tip. It grows in the woods. I have never
seen it. Crown Vetch (Coronilla varia) is a dangerous invasive not found on the preserve. There is a patch of it in a corner of a field just south of Comfort Road on
the west side of Rogers Highway. It has flowers in a clover-like cluster (umbel).
Summary: Invasive vetch has many blue flowers in a one-sided raceme and grows in the open.
Invasive
Native
Native
Garlic Mustard (Alliaria petiolata)
Violet (Viola sp.)
Golden Ragwort (Packera aurea)
Leaves
Garlic Mustard has kidney to heart- shaped
leaves with large rounded irregular teeth.
Location Woods
Bloom
May
start
The leaves are rounder than Garlic Mustard The basal leaves are egg-shaped or roundish,
blunt-toothed and blunt-tipped. The petioles are
and the teeth are smaller.
somewhat purple.
Woods and wetland
May
Woods and sometimes wetland
May
Motherwort (Leonurus cardiac) and Ground Ivy (Glechoma hederacea) have been mistaken for Garlic Mustard but they are also alien so it doesn’t matter if you
accidentally spray them. Once garlic mustard starts to bolt it is easy to distinguish. It is only when leaves first start growing in the spring that it can be confused
with other species.