Ardenwood Regional Preserve

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         (329 plants)
Thanks to the East Bay Regional Park District for this list.

    
Alkali Bulrush
Bolboschoenus maritimus
  • CA Bloom Aug - Sep
  • Flat, narrow stems to about four feet tall.
  • Found near the edge of salt water.
  • Widespread in California and around the world.
  • CA native



Flowers dark brown with tan bristles.

Flowers group in the joint of flat stems.

Stands erect with noticeable brown flowers
American Vetch
Vicia americana ssp. americana
  • Height 1 - 2 ft.
  • CA Bloom May - Jun
  • Flowers with pink, violet and white parts.
  • Tendrils, modified leaves, allow the plant to climb on others.
  • The vine stem can grow to 4 feet long, but the plant is generally under 2 feet tall.
  • Alternate compound leaves.
  • Widespread understory plant.
  • CA native



Small but bright flowers

Lots of small compound leaflets.

Long thin leaves and purple flowers make this a vetch.
Annual Beard Grass
Polypogon monspeliensis

Annual Beard Grass is topped by large, fluffy spikes. They're framed by flat, rough, green leaves to 8" long.

Soft, dense spikelets are green until they mature. There are lots of spikelets in the spike, each producing 3 awns.

Long awns let light through around the edge but the center is opaque.
Annual Blue Grass
Poa annua


Bright green or yellow-green leaves are soft, generally flat and come to a blunt point at the tips.

Like all Bluegrasses, the inflorescence is open and spikelets have no awns. Florets are membranous.

Annual Blue Grass grows quickly in disturbed areas. Plants are small but have many leaves.
Annual June Grass, Bristly Koeleria
Koeleria gerardii
  • CA Bloom Apr - Jul
  • Not CA native




  • Annual Stinging Nettle
    Urtica urens
    • CA Bloom Jan - Apr
    • Also called Dwarf Nettle, this plant grows to about 2 feet tall.
    • Stinging nettles, in general, produce a stinging sensation when touched. However, EFlora says that this specie's sting is not very strong.
    • Found in shady areas.
    • Not CA native



    Leaves are hairy, dark green, have large teeth, and end in a point.

    Leaves are opposite. Veins make indentations in the leaves.

    Small green flowers look like little balls.
    Australian Fireweed
    Senecio glomeratus
    • CA Bloom Apr - Sep
    • Yellow composite flowers group at the top of a branched 6 foot plant.
    • Leaves are alternate and deeply lobed.
    • Found in disturbed sites below 1,000 feet, generally near the coast.
    • Not CA native
    • Moderately Invasive


    Composite flowers group at the top of the stem. They have no "petals" ( ray flowers).

    Leaves clasp the stem, grow to about 6 inches, and are deeply lobed.

    Grows to 6 feet or so, with lots of flowers near the top of the stem.
    Beaked Hawksbeard
    Crepis vesicaria
  • CA Bloom Feb - Oct
  • Yellow flower
  • Many petals
  • Alternate, basal leaves
  • Disturbed
  • Not CA native


  • In the Dandelio sub family. Weedy Hawksbeard has many flat-tipped yellow "petals"

    When viewed from behind, the flower is supported by separate green leaf-like phyllaries.

    Many flowers attach to a single stem. Traditional "ragged" dandelion leaf.
    Bearded Clover
    Trifolium barbigerum
    • Height to 1 ft.
    • CA Bloom Feb - May
    • Brown, pink, violet, white flower
    • Irreg petals
    • Alternate leaves
    • CA native




    Bearded Sprangletop
    Leptochloa fusca ssp. fascicularis
  • CA Bloom Jun - Oct
  • CA native




  • Beardless Wild Rye
    Elymus triticoides


    This rye has 2-ranked spikelets that connect directly to the stem. There is space between each alternating spikelet.

    Hollow stems (like straws) connect at solid joints. Leaves are about 1/4" wide and a foot long.

    Prominent blue-green leaves are 4-12" long and grow away from the stem. Found in moist habitats with heavy soils.
    Bee Plant
    Scrophularia californica
    • Height 2 - 4 ft.
    • CA Bloom Feb - May
    • Bee plant is tall, with prominent triangular leaves and tiny brownish-red flowers.
    • Small flowers are less than 1/2" across and have a nectar disk to reward pollinating bees.
    • Opposite leaves have stalks that connect to the stem.
    • Found in moist places below 8,000 feet.
    • CA native



    This view of the flower from below shows two rounded petals on top, two side petals, and one folded out like a tongue.

    A square stem supports large, opposite, toothed leaves. This might make you think "Mint" but it's not.

    Bee Plant grows several feet high with opposite, narrow leaves sticking straight out. Flowers are on horizontal stalks near the top.
    Bermuda Grass
    Cynodon dactylon

    Spikelets are tiny (<1/10") and purple. Tight colonies of plants are connected by rhizomes and stolons.

    Two rows of spikelets connect to one side of finger-like branches that all join at the top of the stem.

    The ligule is white and hairy. Leaf blades are short, flat and fleshy.
    Big Leaf Mistletoe
    Phoradendron leucarpum ssp. macrophyllum
  • Shrub
  • Green flower
  • Tiny petals
  • Opposite leaves
  • CA native




  • Big Scale Balsam Root
    Balsamorhiza macrolepis
  • CA Bloom Mar - Jun
  • Yellow flower
  • Many petals
  • Basal leaves
  • Slopes
  • CA native
  • Endangered (CNPS 1B)




  • Big Tarweed
    Blepharizonia plumosa
  • CA Bloom Jul - Oct
  • CA native
  • Endangered (CNPS 1B)




  • Bioletti Cudweed
    Pseudognaphalium biolettii
    • CA Bloom Jan - May
    • Flowers are white on the outside and yellow on the inside.
    • Alternate leaves are wide at the base and clasp the stem.
    • Leaves and stem are covered with short fine hair, not sticky but sharply scented.
    • Found in coastal chaparral and in mixed evergreens in the foothills.
    • CA native



    Shiny papery phyllaries surround tiny yellow aster flowers.

    Many tiny brown fruits.

    Grows to 3 feet, sometimes woody at the base.
    Bird's Eye Speedwell
    Veronica persica
    • Height 4 in. - 1 ft.
    • CA Bloom Feb - May
    • This is a small, beautifully marked wildflower.
    • Leaves are opposite and small, often with serrated edges.
    • It's found in disturbed areas, often near agriculture.
    • Not CA native



    The small (1/4"), 4-petaled flower has darker blue, radiant stripes. Notice how the petal sizes vary. 2 purple-tipped stamens and a green tinged center invite pollinators to visit.

    Leaves are opposite. Flowers cluster at the top of the stem. The plant is often recumbent, lying along the ground.

    This beautiful plant is easy to overlook because of its small size, but a pleasure to find.
    Bird's Foot Lotus
    Acmispon brachycarpus
    • Height 6 in. - 1 ft.
    • CA Bloom Mar - Jun
    • Yellow flower
    • Pea petals
    • Alternate leaves
    • CA native




    Bird's Foot Trefoil
    Lotus corniculatus
    • Height to 8 in.
    • CA Bloom May - Jul
    • Tiny fruit clusters look like a bird's foot.
    • Short, thin compound leaves make bundles along the stem.
    • Find it in open grasslands, wetlands, and compacted soil along roads and trails.
    • Other Trefoils
    • Not CA native



    Tiny pea flowers cluster at the end of the stem.

    Each plant is small. See fruit pods on the left, compound leaves in the middle, and a flower cluster on the right.

    Colonies of Bird's Foot Trefoil can be prominent in grasslands. It is sometimes vine-like, with prostrate stems up to 20 inches.
    Black Cottonwood
    Populus trichocarpa
    • CA Bloom Feb - Apr
    • A large riparian tree with alternate leaves
    • Leaf stems are round (Fremont Cottonwood's is flattened).
    • Widely distributed in California, except the central valley.
    • CA native



    Leaf tops are glossy dark-green. Undersides are pale. Leaves are long and pointed, with small teeth on the edge.

    Alternating secondary veins connect to a central one.

    Grows near running water. Trunks get very large, and the tree height often exceeds 100 feet.
    Black Locust
    Robinia pseudoacacia
  • CA Bloom Mar - Jun
  • White flower
  • Pea petals
  • Alternate leaves
  • Not CA native
  • Somewhat Invasive




  • Black Mustard
    Brassica nigra
  • CA Bloom Apr - Jul
  • Yellow flower
  • Four petals
  • Alternate leaves
  • Not CA native
  • Moderately Invasive




  • Blackwood Acacia
    Acacia melanoxylon
    • Height 50 - 100 ft.
    • CA Bloom Feb - Mar
    • This acacia tree has twisted reddish-brown pods.
    • The trunk has high levels of tannin, which causes dark stains when people handle it (thus Blackwood).
    • Generally found in coastal disturbed areas.
    • Not CA native
    • Somewhat Invasive


    Pale yellow spherical flowers show many stamens. These develop into reddish-brown pods.

    Mature leaves are generally wide but occasionally have divided fern-like tips. Young leaves are divided too.

    Blackwood Acacia grows to be a substantial tree.
    Blue Elderberry
    Sambucus mexicana
    • CA Bloom Mar - Jul
    • A large shrub with clusters of white flowers, plus compound leaves indicate an Elderberry.
    • Berries are black but appear blue because of a waxy covering.
    • Grey bark with vertical furrows.
    • Common on stream banks and open places in forests.
    • CA native



    White flat-topped clusters of flowers are easy to spot.

    Berries with a waxy covering makes them look powdery.

    Compound leaves with 5 - 9 toothed leaflets.
    Bog Yellowcress
    Rorippa palustris ssp. palustris
  • CA Bloom Apr - Jun
  • Yellow flower
  • Four petals
  • Alternate leaves
  • CA native




  • Box Elder
    Acer negundo
    • Height 25 - 66 ft.
    • CA Bloom Feb - Mar
    • Opposite leaves
    • Streambanks
    • CA native




    Branched Indian Clover
    Trifolium dichotomum
  • CA Bloom Mar - May
  • Black, brown, pink, white flower
  • Irreg petals
  • Alternate leaves
  • CA native




  • Branching Phacelia
    Phacelia ramosissima
  • CA Bloom May - Aug
  • Violet, white flower
  • Five petals
  • Alternate leaves
  • Coastal
  • CA native




  • Brass Buttons
    Cotula coronopifolia
  • CA Bloom May - Oct
  • Green, yellow flower
  • Tiny petals
  • Alternate leaves
  • Not CA native
  • Somewhat Invasive




  • Brewer's Ragwort
    Packera breweri
  • CA Bloom Apr - May
  • Yellow flower
  • Many petals
  • Alternate, basal leaves
  • Slopes
  • CA native




  • Brewer's Rock Cress
    Boechera breweri
  • CA Bloom Feb - May
  • Violet flower
  • Four petals
  • Alternate, basal leaves
  • Slopes
  • CA native




  • Brewer's Rockcress
    Boechera breweri ssp. breweri
  • CA Bloom Feb - May
  • Violet flower
  • Four petals
  • Alternate, basal leaves
  • CA native




  • Brewer's Saltbrush
    Atriplex lentiformis
  • CA Bloom Jun - Jul
  • Yellow flower
  • Tiny petals
  • Alternate leaves
  • Coastal salt-marsh
  • CA native




  • Bristly Linanthus
    Leptosiphon aureus
  • CA Bloom Mar - Jun
  • Pink, white, yellow flower
  • Five petals
  • Opposite leaves
  • CA native
  • Uncommon (CNPS 4)




  • Bristly Ox-Tongue
    Helminthotheca echioides
    • Height to 7 ft.
    • CA Bloom Jun - Dec
    • A tall dandelion-like flower, covered in bristles.
    • Leaves have large bumps on them.
    • Lots of seed in the fall - you'll see it blowing in the air.
    • Not CA native.
    • Somewhat Invasive


    Leaves have stiff bristles and bumps, giving it its name. Dandelion-like flowers top each branch.

    Dandelion-like flowers are surrounded by distinctive, triangular, upward pointing, bristly green bracts.

    Plants are tall, with many branches.
    Brittle Leaf Manzanita
    Arctostaphylos crustacea ssp. crustacea
    • Height 3 - 10 ft.
    • CA Bloom Jan - Mar
    • Leaves stick out from the hairy stem.
    • Alternate leaves dark green above, and light green below.
    • Big bunches of tiny flowers, hanging down from stalk-like pedicels.
    • Fruit is red and spherical with flat spot. Not sticky.
    • CA native



    Leaves are relatively big (2" long). Flowers are tiny in large bunches.

    Early flower development shows red bracts. Leaves of ssp. crustacea have almost no hair on the bottom.

    Look for a prominent burl at the base of the plant.
    Broadfruit Bur Reed
    Sparganium eurycarpum
  • CA Bloom Jun - Jul
  • Black, brown, green, pink, white, yellow flower
  • Tiny petals
  • Alternate leaves
  • CA native




  • Brome Fescue
    Festuca bromoides


    Brome Fescue is a short grass with small spikelets that turn a straw-like color as they age. Fescue is Latin for "straw".

    Each floret produces an awn about the length of the rest of the spikelet.

    The inflorescence is densely populated with spikelets on short stalks. Spikelets and awns point sideways as they mature, giving a tangled appearance.
    Bulbous Blue Grass
    Poa bulbosa
    • Perennial 6-24"
    • Inflorescence branched 1-4"
    • No awns
    • CA Bloom May - Jun
    • Stems have a bulbous section at their base that can break off to form a new plant.
    • Some plants have bi-sexual florets. Others have aerial bulblets that are self pollinated.
    • Not CA native



    Most California plants have self-pollinated aerial bulblets with shoots already growing out of them.

    The base of the stem also has bulblets that divide to create new plants.

    This weedy bluegrass can dominate roadsides, overgrazed pastures and other disturbed areas.
    Bull Mallow
    Malva nicaeensis
  • CA Bloom Mar - May
  • Pink, violet, white flower
  • Five petals
  • Alternate leaves
  • Disturbed
  • Not CA native




  • Bull Thistle
    Cirsium vulgare
    • CA Bloom June - Sept
    • This thistle has spiny everything.
    • A pear-shaped spiny base supports a 2-inch-tall purple flower.
    • Dead flowers with many spines stay on the plant for a long time.
    • Bull Thistle is common in disturbed areas.
    • Not CA native.
    • Moderately Invasive


    A fairly thin pear-shaped spiny bulge below flower is a good way to distinguish this species.

    Bull Thistle has big spines all the way up the stem, on the leaves, and around the flower.

    Here is a basal rosette of thick, toothed leaves.
    Bur Reed
    Sparganium eurycarpum var. greenei
  • CA Bloom Jun - Jul
  • Black, brown, green, pink, white, yellow flower
  • Tiny petals
  • Alternate leaves
  • CA native




  • Butter And Eggs
    Triphysaria eriantha
  • CA Bloom Feb - Apr
  • Pink, white, yellow flower
  • Three petals
  • Alternate leaves
  • CA native




  • California Aster
    Symphyotrichum chilense
  • CA Bloom Jul - Aug
  • Blue, pink, violet, white flower
  • Many petals
  • Alternate leaves
  • CA native




  • California Aster (1)
    Corethrogyne filaginifolia
  • CA Bloom Jun - Oct
  • Pink, violet, white flower
  • Many petals
  • Alternate leaves
  • Dunes coastal
  • CA native




  • California Bay Laurel
    Umbellularia californica
    • CA Bloom Nov - May
    • Height to 60 feet.
    • The foliage of this classic California tree smells like bay leaves.
    • Clusters of small flowers grow at the end of branches where new leaves emerge.
    • Flowers turn into a plump 1 inch fruit resembling avocados, to which the tree is related.
    • CA Native - endemic to the California Floristic Province.



    Leaves are fairly narrow, with a central vein and smooth edges, ending in a point. They have a leathery feel, and a spicy smell when crushed.

    Green fruit turns purple when mature. Leathery skin covers oily flesh that surrounds a pit (similar to avocado).

    Bay Laurels can grow to be substantial trees, thickly covered with their spicy-smelling leaves.
    California Blackberry
    Rubus ursinus
    • Height 3 - 6 ft.
    • CA Bloom Feb - May
    • This shrub forms an impenetrable thicket of branches, full of narrow prickles.
    • You'll notice bright white flowers with many stamens.
    • Found in canyons, coastal stream banks and disturbed areas
    • CA native



    Separate petals, with green leafy sepals in between. This male flower has many stamens.

    Prickles are short, narrow, and plentiful. Himalayan Blackberry has wider, longer, and less densely-packed prickles.

    Red fruit turns black with maturity. Leaves in 3s, coarsely toothed, are hairy and have spines. Veins are indented on the leaves.
    California Brome
    Bromus sitchensis var. carinatus


    Spikelets attach to the stem on branches. Glumes are short, revealing 5-10 florets above them.

    Florets form a flat, woven pattern, each with a 1/2" awn.

    Long leaves and inflorescences give this a classic bunch grass look.
    California Buckeye
    Aesculus californica
    • Height 12 - 40 ft.
    • CA Bloom May - Jul
    • Buckeye trees are conspicuous from afar; pale green leaves in early spring, full of flowers in early summer, and bare-branched well before other trees lose their leaves in the fall.
    • Each aromatic flower has 4 pink or white petals and long stamens.
    • The fruit resembles a buck's eye - brown and about 2 inches across.
    • CA native



    Buckeye trees become covered with columns of sweet-smelling flowers.

    5-part compound leaves are palmate (shaped like a hand). Leaf edges are finely-toothed and bud in early February.

    Trees in the open form a dome shape, often growing 40 feet tall and 40 feet wide. They can live 250 years.
    California Bulrush
    Schoenoplectus californicus
  • CA Bloom May - Jun
  • Freshwater-marsh
  • CA native




  • California Burclover
    Medicago polymorpha
    • CA Bloom Feb - Jun
    • This is not a true clover but rather a close relative of Alfalfa, in the Medicago genus.
    • Look for slender-toothed stipules that encircle the stem where stalks meet it.
    • Not CA native
    • Somewhat Invasive


    3 or 4 yellow pea flowers cluster at the end of a long stalk. Leaflets have serrated edges.

    Burclover tends to run along the ground. The 3 clover-like leaflets are separate from one another. Flowers, fruits and leaves are on stalks.

    Pollinated ovules enlarge into tightly coiled pea pods with burs that stick out. The burs catch on passing animals, distributing the seeds to new areas.
    California Cottonrose
    Logfia filaginoides
  • CA Bloom Mar - Jun
  • Green flower
  • Tiny petals
  • Alternate leaves
  • CA native




  • California Cudweed
    Pseudognaphalium californicum


    Each tiny pineapple-shaped flower head is wrapped in white papery phyllaries and contains over 100 minute yellow flowers.

    Leaves are narrow and pointed, growing to 4 inches long. They're smaller higher on the stem.

    Branching stems grow erect, each topped with whitish flower heads.
    California Four O'clock
    Mirabilis laevis var. crassifolia
  • CA Bloom Dec - Jun
  • Pink, white flower
  • Five petals
  • Opposite leaves
  • CA native




  • California Goldenrod
    Solidago velutina ssp. californica
  • CA Bloom Jul - Oct
  • Yellow flower
  • Many petals
  • Alternate leaves
  • CA native




  • California Hazelnut
    Corylus cornuta ssp. californica
    • CA Bloom Jan - Mar
    • This shrub has open branching, and grows to 10 feet.
    • Leaves are soft, alternate, and deeply veined.
    • The stem changes direction at each leaf node.
    • Found on stream banks and slopes
    • CA native



    Soft fuzzy leaves have toothed edges. Veins are indented. Leaves fall off in the winter.

    The flower matures to a hazelnut, protected by a hard shell and fuzzy sheath.

    Male catkins form in the fall and last until spring.
    California Honeysuckle
    Lonicera hispidula
    • CA Bloom Apr - Jul
    • This is a woody vine that can climb 30 feet into trees. You'll notice them hanging down from branches.
    • Vines end in pink trumpet flowers whose lips fold back to reveal long stamens.
    • Common in canyons, stream sides and woodlands, especially near the coast.
    • CA native. Endemic to the California Floristic Province.



    Vines end in pink flowers, full of nectar (thus, Honeysuckle). Hummingbird and bees pollinate the flowers in their search for the nectar.

    Pollinated flowers turn into bright-red translucent berries.

    Leaves near the flower wrap around the stem. Leaves further down are opposite.
    California Mustard
    Caulanthus lasiophyllus
    • CA Bloom Mar - Jun
    • Flowers with 4 widely-separated petals mark this as a Mustard Family plant.
    • It's smaller in stature than our vigorous non-native mustards.
    • CA native



    Compared to our non-native mustards, California Mustard has fewer, smaller, generally white flowers.

    Seed pods are quite narrow and long.

    The whole plant gives a linear apearance.
    California Oatgrass
    Danthonia californica


    This bunch grass has flat leaves, about 8" long. Flowering stems arch outwards from the plant center.

    Only 3-6 spikelets in a short inflorescence (about 2"). Branches are flexible and longer than the spikelets.

    Mature spikelets open up, with glumes longer than individual florets. There are 3-8 florets per spikelet.