A wash of prickly, pale green stems is scattered across a dry field. Yellow flowers are surrounded by a mean halo of long narrow thorns. Here is yellow star-thistle (Centaurea solistalis) one of the nastiest invasive plants around. It’s a big problem on farmland and in wild places along the west coast. It interferes with grazing, and eventually leads to permanent brain damage in horses that eat it.
Introduced in the 1850s, this thistle is now the most widespread invasive plant in California, infesting between 10 and 15 million acres in the state. A native to southern Europe, it probably first came to the US indirectly, along with alfalfa seed imported from Chile. By the early 1900s it was a serious weed in the Sacramento Valley and was spreading quickly along roads, railways, trails and streams, according to the CalIPC. “It is a thousand times as common as ten years ago, and perhaps even six years ago,” observed Willis Jepson in 1919.
Things have only gone downhill from there! And it’s not surprising why. This deeply taprooted annual invades summer-dry grasslands across most of the US. A single large plant can produce nearly 75,000 seeds, and blooms from late spring through fall. It’s largely pollinated by honeybees but doesn’t have much in the way of predators, and so it continues to spread.
Delicate pale purple flowers grow in a low mat of green leaves on the forest floor. It’s worth stopping and getting close to check out the lovely little blooms. Five narrow, pointed petals curve backwards, away from a long slim purple-dusted pistil. As the flower matures, the pistil opens into three parts for receiving pollen.
Other names for this Asyneuma prenathoides include California harebell and slender bluebell, but I have always known it by the name found in the Peterson Guide. It once was in the Campanula genus along with the more traditional-looking bluebells but somewhere along the line it was re-assigned to a different group (something that happens a lot in botany as new features, genetic analysis, or other information comes to light).
A flash of pale yellow underneath a coyote bush. Growing up under the gray branches of the shrub is a stalk holding several pretty, broad-faced flowers. The five petals surround a hairy, reddish-pink cluster of stamens. The stamens and pistil are flamboyant: the three upper stamens are clustered together, while the lower ones–and the pistil–scoop outward, presumably an invitation to insects.
This unusually striking flower is moth mullein (Verbascum blattaria), and unfortunately it’s not a native to California. It was introduced from Eurasia and has spread across much of the United States. Other species of mullein share the distinctive hairy-ness and the unusual stamen-and-pistil pattern, but otherwise look quite different.
This gooseberry is a prickly delight. From its elegant branches to its troublesome little berries, Ribes menziesii has a lot of character. The berries are edible–and yummy!–but you have to get past the spines to enjoy them. There’s no easy way to do this; you can try peeling with a pocket knife or just chewing carefully. I’ve also tried popping them with my teeth first, before chomping down. This seems to work the best, but you’re still bound to get prickled a few times.
Overall this plant is better for looking at than for eating, especially in spring and summer. The thorny branches sport scalloped green leaves on gracefully arching branches, and in the spring it puts out masses of small lantern-shaped flowers that bees love.
Gooseberries are a type of currant, and some of the local wild species (spreading gooseberry, flowering currant) are spineless–as are their store-bought cousins. In addition to the canyon gooseberry featured here, there are some other spiny species around as well (California gooseberry and Victor’s gooseberry). You can tell them apart because the first has smooth, hairless leaves and the second has shorter spines on the fruit that are all about the same length.
A sprawling pale-stemmed bush is decked with dark purple raspberries. Warmed in the sun, they have a mild, rich sweetness. These tasty fruits are smaller, leaner, and much darker than their plump commercial cousins. I’ve always preferred the wild version!
There are many listed names for Rubus leucodermis (western raspberry, white stemmed raspberry and whitebark raspberry) but I’ve always just called this “wild raspberry” since it’s the only native one around. It’s in the same genus as Himalayan blackberry, but though the plants are similar they are easy to tell apart even when not in fruit. Western raspberry is a delicate shrub with slim branches that have a glaucous coating which you can rub off with a finger. The leaves of both species are three parted, but blackberries’ are much thicker and darker.
Western raspberry is one of my very favorite California berries, but you won’t see it growing in Marin. Sonoma County? Yep. Santa Cruz? Yep. Even down to San Diego and up into Alaska. But for some reason it doesn’t like the San Francisco bay – there’s no record of it in SF, Marin, the East Bay, or the Peninsula.
In ditches and along river banks, the berries are beginning to ripen. Great green mounds of shrubs – all leaves and thorny branches – are speckled with dark purple fruit. Younger berries are still green or red, and most bushes still have flowers on them as well.
This is the Himalayan blackberry (Rubus armeniacus), one of the most common berries around. It is also one of the only non-native invasive berries in the area. Though it’s delicious in pies, smoothies and endless other treats, this shrub can be a nasty problem for native habitats: I’ve seen it smother entire fields, leaving no space for native plants and the animals that depend on them. Usually you’ll see it in disturbed places and on poor soils. Despite the name, the bush originally came from western Europe and there is “no evidence” that it came from the Himalayas.
One nifty thing about this “fruit” is that it’s actually a bunch of small fruits – each little nub on the berry is called a “drupelet” in botany-speak.
Here is a common little tarweed with small unobtrusive flowers. Madia gracilis has the strong odor and sticky stem that’s common to the tarweeds (or gumweeds, which is another one of this little guy’s common names). The flowers are often dwarfed by the bulbous green cup of sepals below. If you look close you’ll see that the entire plant is covered with little glandular hairs, with tiny black dots atop stubby white bristles.
A spike of striking purple flowers rises from the tangle of greenery in a low wetland. Here is the coast hedge nettle, or Stachys chamissonis. This is a lovely summer bloomer that grows several feet tall and boast big showy flowers. The Flora of Marin went so far as to call this “one of our most attractive flowering plants.” High praise given the stiff competition.
Check the square stem and pairs of simple leaves for a good guess as to what family it is in!
With a spiky green sheath of bracts surrounding several layers of purple petal-like flowers, salsify (Trapopogon porrifolius) is a beautiful and slightly cruel looking plant. The inner flowers of the head are dusted with yellow pollen that is the perfect ornament on the dark purple petals. Each of the large-ish, showy flowers is actually many flowers, since this is a member of the Asteraceae family. Once the flower has gone to seed, it produces a big dandelion poof that can be a few inches across.
This plant is also called oyster-root, and it was introduced from Europe where the carrot-like root is eaten; the flavor is described as similar to oyster or artichoke. Here in California it is an escaped ornamental, and likes to grow in dry grassy areas. You usually will see it in disturbed places, not too far from town.
With flamboyant, showy flowers, Spanish broom is probably the most beautiful of all the evil brooms. It is still evil, though. Don’t be fooled by the big yellow flowers with their many exuberant stamens and pretty wing-like petals.
This plant has the lean, linear look of Scotch broom but with even fewer leaves. The California Invasive Plant Council lists Spanish broom (Spartium junceum) as a species that can cause serious problems for native ecosystems. It can grow up to 15 feet tall and form dense stands that smother all other plants in the area. According the IPC, it is native to Spain, Morocco and other parts of southern Europe. It was introduced to California in 1848 as a decorative plant, and in the 1930s was planted along mountain highways in Southern California. Oops.
In Marin, it is one of the least common brooms. I saw the ones pictured here clinging to the slopes of what looks like an old rock quarry owned by the Marin Municipal Water District.