Weeds: Knapweeds – Centaurea spp. categories: I-Po Weeds last review date: 2025-09-22 09:57 Family: Asteraceae (Compositae) Cycle: Biennial/perennial Plant type: Broadleaf Spotted knapweed flowerheads Photo by: B.F. Roche Biology Knapweeds are short-lived perennials with stout taproots. They can have one or more stems, reaching one to three feet in height. Depending on species, leaves may […]
Weeds: Knotweeds (Bohemian, Giant, Japanese, Himalayan) – Polygonum spp. categories: I-Po Weeds last review date: 2025-09-24 01:54 Family: Polygonaceae Cycle: Perennial Plant type: Broadleaf Japanese knotweed leaves Photo by: J.A. Kropf Biology The giant knotweeds are aggressive plants that spread via long rhizomes and also by seeds. They are deciduous plants, with the woody, reddish-brown […]
Weeds: Kochia – Kochia scoparia categories: I-Po Weeds last review date: 2025-09-24 01:59 Family: Chenopodiaceae Cycle: Annual Plant type: Broadleaf Kochia showing fall color Photo by: J.A. Kropf Biology Kochia has a single stem reaching one to six feet high. The main stem is branched above, but typically unbranched at the base. Leaves are soft, […]
Weeds: Lambsquarters, common – Chenopodium album categories: I-Po Weeds last review date: 2025-09-24 02:01 Family: Chenopodiaceae Cycle: Annual Plant type: Broadleaf Common lambsquarters Photo by: T.W. Miller Biology Common lambsquarters is typically an upright, branching plant growing one to four feet high from a taproot. The stems are ridged or angular in cross-section and may […]
Weeds: Lesser celandine – Ficaria verna categories: I-Po Weeds last review date: 2025-09-24 02:02 Family: Ranunculaceae Cycle: Perennial Plant type: Broadleaf Lesser celandine close-up Photo by: S. Campbell Biology Lesser celandine is a noxious weed. It is highly variable and has club-shaped, tuberous roots. The weed grows as a mounded rosette with basal and stem […]
Weeds: Liverworts – Several species categories: I-Po Weeds last review date: 2025-10-12 06:47 Family: Various Cycle: Plant type: Bryophyte (mosses & liverworts) Liverworts in pot Photo by: J. Altland Biology Liverworts are low-growing, non-flowering relatives of mosses. They are typically small plants that grow prostrate on the ground. Lacking true roots, they are attached to […]
Weeds: Mallow, common (Cheeseweed, Buttonweed) – Malva neglecta categories: I-Po Weeds last review date: 2025-10-12 06:53 Family: Malvaceae Cycle: Various Plant type: Broadleaf Mallow flower Photo by: T.W. Miller Biology Common mallow can be an annual, winter annual, or biennial plant. The plants are spreading from a deep root, with branches reaching from a few […]
Weeds: Nightshades – Solanum spp. categories: I-Po Weeds last review date: 2025-10-12 06:57 Family: Solanaceae Cycle: Annual/Perennial Plant type: Broadleaf Cutleaf nightshade with fruit Photo by: D.G. Swan Biology Nightshades are annual or perennial taprooted plants that spread by seeds. They usually have spreading, branched stems to three feet tall. The alternate leaves are broad […]
Weeds: Oxalis (Creeping woodsorrel) – Oxalis corniculata categories: I-Po Weeds last review date: 2025-10-12 07:24 Family: Oxalidaceae Cycle: Perennial Plant type: Broadleaf Woodsorrel leaves and flower Photo by: J.A. Kropf Biology Creeping woodsorrel is a prostrate plant, initially growing from a slender taproot. Branches lie flat on the ground, rooting at the nodes to form […]
Weeds: Parrotfeather and Eurasian watermilfoil – Myriophyllum spp. categories: I-Po Weeds last review date: 2025-10-12 07:28 Family: Haloragaceae Cycle: Perennial Plant type: Broadleaf aquatic Partotfeather fronds Photo by: T.W. Miller Biology These rhizomatous perennials exhibit an annual pattern of growth. In the spring, shoots begin to grow rapidly from overwintering rhizomes as water temperatures increase. […]
Weeds: Pineappleweed – Matricaria discoidea categories: I-Po Weeds last review date: 2025-10-12 07:36 Family: Asteraceae (Compositae) Cycle: Annual Plant type: Broadleaf Pineappleweed heads and leaves Photo by: T.W. Miller Biology Pineappleweed grows to over one foot in height, with leaves finely divided into narrow, feathery segments. Cone-shaped or rounded yellow-greenish flowers are produced singly at […]
Weeds: Plantain (Broadleaf, Buckhorn) – Plantago spp. categories: I-Po Weeds last review date: 2025-10-12 07:39 Family: Plantaginaceae Cycle: Perennial Plant type: Broadleaf Broadleaf plantain Photo by: R. Parker Biology Broadleaf plantain leaves are all basal, forming a low-growing rosette. Broadleaf plantain bears many fibrous roots, from which new plants can occasionally arise. The crown of […]
Weeds: Poison hemlock – Conium maculatum categories: I-Po Weeds last review date: 2025-10-13 10:46 Family: Apiaceae (Umbelliferae) Cycle: Biennial Plant type: Broadleaf Poison hemlock leaves Photo by: T.W. Miller Biology Seedling poison hemlock plants are rosettes of finely divided fern-like leaves which closely resemble carrot leaves. Mature plants grow six to eight or more feet […]
Weeds: Poison ivy and Poison oak – Toxicodendron spp. (Rhus spp.) categories: I-Po Weeds last review date: 2025-10-12 07:52 Family: Anacardiaceae Cycle: Perennial Plant type: Broadleaf Poison ivy leaves Photo by: J.A. Kropf Biology Western poison ivy (Toxicodendron rydbergii) is a woody shrub or occasionally a climbing woody vine that may reach 3 to 9 […]
Weeds: Pokeweed: Phytolacca americana categories: I-Po Weeds last review date: 2025-10-12 07:55 Family: Phytolaccaceae Cycle: Perennial Plant type: Broadleaf Pokeweed plant Photo by: K. Volkov Biology Pokeweed is a shrub-like herbaceous perennial. It can grow quickly to a height of up to 10′ in one year. The central stem bears egg-shaped leaves which can range […]
