What’s Up With Weeds: February 2015

Your cure for cabin fever

February is the time of the year when Oregonians start to experience the late stages of cabin fever. After the months of shortened days, cold temperatures, rains, and cloud cover our usually pale complexions rapidly trend toward translucence. But February also offers the first glimmers of hope of the spring ahead.

By late February we start to see the cold and dreary days of winter giving way to a few sun breaks. The catkins start forming on Red Alder (Alnus rubra), and the first green leaves and white blossoms of Indian Plum (Oemleria cerasiformis) make their first appearance. Home landscapes become dappled by the ever popular crocuses and daffodils that start tempting us back outdoors.

Western Bleeding Heart (Dicentra formosa)

Western Bleeding Heart (Dicentra formosa)

The best part of February is that even though we still have several months of wintry weather remaining, it gives us hints of spring and assures us that the worst of the season is over. This makes February the perfect time to plant new plants outside. The cool wet weather still to come helps to promote root growth of new plantings, helping keep new plantings from drying out. So if you are looking to plant, February could be the best time to get outside and cure your cabin fever.

Report Weeds!
Early detection is the key

The enemy of my enemy is my friend

The approach often used to control invasive weeds amounts to “subtractive restoration.” We focus on the invasive species and often feel a sense of accomplishment when eradication results in bare ground without those nasty weeds. But Nature abhors bare ground and will not tolerate it for long. We hope that the surrounding vegetation will respond to fill in the gaps we have created, but if we are not careful we end up replacing our weeds with a new set of weeds. Planting or seeding disturbed areas is one of the best ways that you can help to combat this problem.

Planting desirable plants is one way to control invasive weeds. One of the most common and desirable ways to combat a species like Reed Canary grass (Phalaris arundinacea) is by planting into patches with woody shrubs and trees that will eventually shade out this weed. In this way, plantings are a great tool that should be in everyone’s management toolbox. For some great tips on planting check out the Riparian Tree and Shrub Planting Guide.

This February — while you are trying to figure out who first calculated the importance of a groundhog’s shadow in relation to climate — take the long President’s Day weekend to plant some plants with your valentine. I recommend the native bleeding heart (Dicentra Formosa) to help set the mood. The little bit of time spent outside will provide the shot of vitamin D you just might need to help shake off the winter blues and cure your cabin fever.


So what is up with Weeds in February?

Grass-like plants

  • Jubata grass (Cortaderia jubata) is an annual shrub that follows the same timeline as Pampas grass. Plants have seeded. Dig up the entire plant.
  • Common reed grass (Phragmites australis) is a grassy perennial. Plants that were emerging in April, May, and June have seeded, dig up any plants and dispose in trash.
  • False brome (Brachypodium sylvaticum) is a perennial grass. Plants have seeded and going dormant. Please [contactweedwise] if you see false brome!

Herbaceous flowering plants

  • Russian knapweed (Acroptilon repens) bolts in May with flowers appearing in June, July, and August. Control can be through handpulling, tilling, mowing, or digging. Root fragments resprout so it’s important to get all of the plant out of the ground.
  • Garlic mustard (Alliaria petiolata)was forming rosettes through the winter and flowers in April and May. Seeds may be present and viable from June through September! You can hand pull plants, although root fragments can resprout. Please [contactweedwise] if you see garlic mustard!
  • Spotted knapweed (Centaurea biebersteinii) follows the same timeline as Diffuse knapweed. Dig up the entire plant (easier when soil is moist in the spring).
  • Purple starthistle (Centaurea calcitrapa) sprout from seed in winter and develop into rosettes in spring. Starthistle plants flower from July to Spetember. Please [contactweedwise] if you see purple starthistle in your area.
  • Meadow knapweed (Centaurea debeauzii) follows the same timeline as Diffuse knapweed. Dig up the entire plant (easier when soil is moist in the spring).
  • Diffuse knapweed (Centaurea diffusa) is a herbaceous perennial. In May, plants bolt. Flowers appear in May, June, and July. Dig up the entire plant (easier when soil is moist in the spring).
  • Yellow starthistle (Centaurea solstittialis) sprout from seed in winter and develop into rosettes in spring. Starthistle plants flower from May to July. Please [contactweedwise] if you see yellow starthistle in your area.
  • Rush skeletonweed (Chondrilla juncea) bolts in April, May, and June. When it flowers in July, it sets seed quickly!
  • Paterson’s curse (Echium plantagineum) emerges in March and April, flowering all summer.
  • Orange hawkweed (Hieracium aurantiacum) can be dug up in March and April. Be sure to get the roots and runners. Flowering occurs in May and June, and can extend later, with flowers and seeds occurring from July through September. More information is available on the Oregon Department of Agriculture’s page about Orange hawkweed. Please [contactweedwise] if you see Orange hawkweed!
  • Yellow-flag iris (Iris pseudacorus) is a herbaceous perennial that emerges in April and flowers in May and June. Seeds are set from July through September
  • Yellow archangel (Lamiastrum galeobdolon) is a herbaceous perennial the grows throughout the winter and flowers from April to June. Seeds are set in July and August.
  • Kudzu (Pueraria lobata) is a vining perennial. Leaves emerge in April, May, and June. Flowers emerge in July. Please [contactweedwise] immediately if you think you have spotted Kudzu in Clackamas County!
  • Lesser celandine (Ranunculus ficaria) is a herbaceous perennial. Rosettes form in January and February, and the plants flower in March. In April, seeds are set. Remove all of the bulblets and tubers.
  • Tansy ragwort (Senecio jacobaea) is a herbaceous biennial. Rosettes form in March and April, and flowers in May, June, and July. If soil is moist, dig up the rosettes. If you remove the plant during flowering, bag the plant so seeds can’t spread.

Shrubby plants

  • Blessed milk thistle (Silybum marianum) overwinter as rosettes that bolt in March, April, and May. The plants flower in June and July. Mow or hand pull before flowers fully develop.
  • Butterfly bush (Buddleia davidii), a tall deciduous shrub, displays new leaves in April, May, and June, but doesn’t generally flower until July and August. Control by digging up the entire plant. Our Weed Wrench might work!
  • Giant hogweed (Heracleum mantegazzianum) is a tall herbaceous perennial. Plants emerge in March and April from winter rosettes, and accelerate in growth in April and May. When the plants flower in June and July, remove the heads and cut off the plant at the base…but be very careful because the sap of this plant is caustic. ODA says this about Giant hogweed: “This plant is a public health hazard. Do not expose bare human skin to the plant or breathe the smoke from fires if it is being burned. The plant exudes a clear watery sap which sensitizes the skin to ultraviolet radiation. Humans often develop severe burns to the affected areas resulting in blistering and painful dermatitis. Blisters can later develop into purplish or blackened scars.” Please [contactweedwise] immediately if you spot this plant!
  • Gorse (Ulex europaeus) is a single to multi-stemmed spiny shrub that buds in February and flowers in March, April, and May. It goes to seed in June and July. Dig up small plants. Please [contactweedwise] if you see gorse!
  • Policeman’s helmet (Impatiens glandulifera) is a herbaceous annual the begins to emerge in April and grows through May. Flowers appear in June and July.
  • Purple loosestrife (Lythrum salicaria) is a herbaceous perennial that emerges in May and June. Flowers begin to appear in July.
  • Scotch thistle (Onopordum acanthium) is a herbaceous biennial that overwinters as rosettes. Flower stalks emerge in June and flowering is in July and August.
  • Spurge laurel (Daphne laureola) is an annual shrub that emerges in March and flowers in April, May, and June. Berries appear in June and July. Dig up as much of the plant and root system as possible. Please [contactweedwise] if you see spurge laurel!
  • Knotweeds include Japanese knotweed (Polygonum cuspidatum), Giant knotweed (Polygonum sachalinense), Himalayan knotweed (Polygonum polystachyum), and hydrid knotweeds began emerging in April. With warmer temperatures, growth accelerates throughout May and June. Flowers emerge in July and August. Mechanical control requires frequent, persistent effort: cut twice each month from April through August. In the fall, additional steps are needed, including cutting and covering the plants. Knotweeds are so persistent that you need to do this repeatedly for five years to achieve control.

Aquatic plants

  • Parrot’s feather (Myriophyllum aquaticum) is a perennial with underground rhizomes that overwinter. Stems emerge in April and May. Flower stalks appear in June and July. Removing the entire plant, including root fragments, is necessary.

Report weeds!

Visit our page on reporting weeds to file a report.

Report Weeds!
Early detection is the key

Photo courtesy of: Walter Siegmund, Wikicommons

Photo is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.

 

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