Sweet Alyssum (Lobularia maritima).
A popular bedding plant that liberally seeds itself.
When seeds get washed downhill, they lodge in sidewalk
cracks, where they’re quite happy to grow and bloom
all summer and well into fall, producing more seeds to
lodge in sidewalk cracks, and making the garden
Alyssum one of our more common urban weeds.
Field Pennycress (Thlaspi arvense).
An unimposing little weed, but it delights children by
producing round, flat seedpods that look like coins.
The lesson to be learned here is that adults do not
judge plants as children do, and perhaps children have
a better sense of what is valuable than adults have.
This plant grew in a meadow near Cranberry, where it
was blooming and already seeding in the middle of
June.
Lepidium
Charlock (Sinapis arvensis).
Formerly placed in the genus Brassica, and
also formerly called Brassica kaber. A
common weed along roadsides and in fields. It has the
typical four-petaled mustard flowers in the typical
mustard-yellow color, but the larger flowers easily
distinguish it from the other wild mustards.
Capsella
Garlic Mustard (Alliaria petiolata).
An invasive weed that came from Europe because it is a
tasty and useful vegetable. It is much hated by
wildflower connoisseurs, who accuse it of crowding out
the natives in spring. The best thing to do with it is
probably to eat it.
Tumble
Mustard (Sisymbrium altissimum). Not
common, but locally abundant. This is a
summer-blooming mustard with small yellow flowers;
tall when it’s allowed to grow, but it will bloom
short in a mowed lawn. When the (annual) plant is
finished, it dries up and detaches from its roots,
tumbling along the ground. Unlike a tumbleweed, Tumble
Mustard is well and truly dead when it tumbles, but
while the corpse travels it flings its seeds
everywhere.
Dame’s Rocket (Hesperis matronalis).
Pittsburghers usually call it “phlox,” or—as we have
heard a Pittsburgher say—“some sort of phlock.” But
this ubiquitous late-spring flower is really a member
of the mustard or crucifer family, as you can tell by
the four-petaled flowers (real Phlox flowers have five
petals). It came from Europe as a garden flower and
quickly made itself at home. It would be hard to
conjure up any inhospitable feelings toward this
welcome guest, whose bright flowers decorate roadsides
and back yards everywhere. Each colony blooms in a
mixture of colors from deep magenta to white, and many
plants grow flowers with splashes or stripes of
contrasting colors.
Rorippa
Watercress (Nasturtium officinale).
Watercress likes to grow with its feet in the edge of
a lazy stream. The main blooming season is in the
spring, but the cool weather of fall seems to give the
plants their second wind, and our picture comes from a
colony that was blooming profusely in late October.
Armoracia
Barbarea
Broad-Leaf Toothwort (Cardamine
diphylla). Just as the Cut-Leaf
Toothworts (C. concatenata) are winding down,
the Broadleaf Toothworts open up. They are not as
common as the Cut-Leaf Toothworts, but they like the
same wooded hillsides, especially in stream valleys.
Broad-Leaf Toothwort is easily distinguished by its
two leaves with three broad leaflets each (C.
concatenata has three leaves with very narrow
lobes).
Cut-Leaf Toothwort (Cardamine
concatenata). Cut-Leaf Toothworts are
quite variable. They all have four-petaled white to
slightly pink flowers and three finely cut leaves, but
different populations are notably distinct in form,
with flowers and leaves varying over a wide range.
Hairy Bittercress (Cardamine hirsuta).
Depending on your point of view, this is either an
invasive weed or a cheery harbinger of spring. It
comes from Europe, and it makes itself at home in our
lawns, where it politely refuses to exceed the height
of the grass around it. There are people who eat it as
a salad herb, so it can’t be all bad. It’s one of the
first things to bloom in the spring, appearing along
with the crocuses and persisting through daffodil
season.
Spring Cress (Cardamine bulbosa).
A relative of the Toothworts (which most botanists now
also place in the genus Cardamine), this
pretty little flower seems to like damp locations.
This one was growing in a damp open woods in Bird Park
in Mount Lebanon, where it was blooming in early May.
The round leaves (changing to long and narrow as they
go up the stem) distinguish this from other common
species of Cardamine in our area.
Arabis