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weed tall lavender puff ball seeds northern ca

JP: Yes, people are probably too touchy about weeds. Our need for perfection leads to an intolerance of weeds. Some weeds add benefit to our gardens and ecosystems so it's important to be informed and know what to yank and what may be worth leaving alone. That being said, we do need to be careful to not let things get out of control.

Do you have a good tip for reducing weeds? Tell us about it in the comments below.

What should you do if you aren't sure if it's a weed or a flower?

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What is your personal favourite weed and why?

What makes a weed, a weed?

JP: In my job at Royal Botanical Gardens, I'm always working with the scientific binomial names of plants and I love the scientific names of a bunch of weeds. Medicago lupilina commonly known as Black Medic for example, is a common weed in lawns and gardens and I just love the way it rolls off the tongue.

Canada Thistle (Cirsium arvense) sounds like it's native to Canada however, it's actually a descendent from Asia and Europe and should be called 'Creeping Thistle' or 'Field Thistle' in order not to confuse us. This "noxious weed" reproduces by wind-dispersed seed and by a colonizing root system which allows it to form dense patches or monocultures. Canada Thistle is a ruderal species — a species which is first to colonize disturbed land. The spread by an underground network of roots, along with the spiny leaf edges and stems, make this weed difficult to deal with in any situation. Though it's a pest in the garden, this species also plays an important role in the ecosystem. Its purple flowers are visited by a wide variety of insects, the seeds are an important food source for birds like goldfinch and its leaves are used as food by many species of butterflies and moths.

(Amaranthus palmeri S. Watson)

Yellow toadflax tends to be found in more moist areas than dalmatian toadflax and has become a weed in lawns as well as roadsides, pastures and disturbed areas. Yellow toadflax can be mildly poisonous to livestock that graze it. Mecinus janthinus is under evaluation for yellow toadflax control.

Spring- and fall-emerging plants can reduce wheat yield but are easily controlled with sulfonylurea herbicides. False chamomile has been used for medicinal purposes for hundreds of years. The plant is used to make chamomile tea which is reported to have relaxation benefits. Pollen from this plant will cause allergic reactions similar to ragweed.

Narrowleaf hawksbeard

Kochia is a widespread weed found in cropland, roadsides, waste areas and overgrazed pasture. Kochia is a taprooted annual forb that can grow from 1 to 6 feet tall. Seedlings are very pubescent. Stems are erect and spreading, much branched and yellowish-green to green, which turn red with maturity. The leaves are alternate, lance-shaped and 0.5 to 2 inches long, with fringed hairs on the margins. Kochia flowers are inconspicuous, greenish, and form short, dense, terminal, bracted spikes. Flowering is from July to September. The plant spreads only by seed with more than 14,000 produced per plant.

Downy brome can displace desirable forage quickly and reduce crop yields. The plant grows in high densities and can be a ready fuel source for fires because it dries down early in the growing season. Downy brome is palatable to livestock very early in the growing season, but the long awns of the seed cause sores in the mouth and eyes. The plant is especially weedy in winter wheat.

State listed

Leafy spurge is a long-lived perennial that spreads by root and seed. The plant grows 2 to 3 feet tall, with alternate, bluish-green narrow leaves about 2 inches long. Showy yellow bracts appear in May and June, but the true flowers are small and green. Seed pods contain three gray-brown, oblong seeds that mature in mid-July. The plant contains latex, so most animals avoid grazing until late fall.