{"id":28773,"date":"2022-07-11T08:35:33","date_gmt":"2022-07-11T12:35:33","guid":{"rendered":"https:\/\/extension.umaine.edu\/publications\/?page_id=28773"},"modified":"2024-05-23T12:32:18","modified_gmt":"2024-05-23T16:32:18","slug":"2584e","status":"publish","type":"page","link":"https:\/\/extension.umaine.edu\/publications\/2584e\/","title":{"rendered":"Bulletin #2584, Hawkweed in Maine Lawns"},"content":{"rendered":"\n

Bulletin #2584, Hawkweed in Maine Lawns (PDF)<\/a><\/p>\n\n\n\n

Adapted by Donna Coffin, Extension Professor, University of Maine Cooperative Extension<\/em><\/p>\n\n\n\n

For information about UMaine Extension programs and resources, visit extension.umaine.edu<\/a>.<\/strong>
Find more of our publications and books at extension.umaine.edu\/publications\/<\/a>.<\/strong><\/p>\n\n\n\n

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Orange hawkweed flower stem detail.<\/figcaption><\/figure><\/div>\n\n\n

Introduction<\/strong><\/h3>\n\n\n\n

In Maine, hawkweed is not on the state’s invasive plant list, although it is in other states. Hawkweed can be a concern to homeowners with lawns that get infested with it. It can also be a problem where the grass is not thriving due to low fertility, dry soils, or compaction. It can also be a problem in pastures and hayfields.<\/p>\n\n\n\n

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Hawkweed does have a few redeeming qualities for pollinators. Beauty is in the eye of the beholder. If you don’t mind seeing these little yellow or orange flowers spring up above your grass and you are in low maintenance mode for your lawn, it’s not a problem. If you want a perfect uniform green grass lawn, then yes, you need to control it.<\/div>\n\n\n\n

Identification<\/strong><\/h3>\n\n\n\n

Hawkweeds are in the sunflower family with milky juice, yellow or orange dandelion\u2010like flower heads, and are bristly\u2010hairy overall. Plants have rosettes of strap or lance\u2010shaped leaves at the base of the stem. Basal leaves of most non\u2010native hawkweeds usually persist through flowering. Hawkweeds hybridize freely with native and non\u2010native species and are very difficult to identify species.<\/p>\n\n\n\n

Many non\u2010native hawkweeds have stolons (runners), allowing for aggressive vegetative reproduction. It is an indicator plant for infertile soils. Native hawkweed species do not have stolons, although some non-native hawkweeds lack them, too. Orange hawkweed (Hieracium. aurantiacum<\/em>) has been reported to be allelopathic. This means it can inhibit the germination of other plants by producing toxic chemicals in the surrounding soil. In early spring during cool weather hawkweed leaves may appear purplish, but green up with warmer temperatures.<\/p>\n\n\n\n

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1. Identify the patch of hawkweed in the lawn.<\/figcaption><\/figure>\n\n\n\n
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Yellow and orange hawkweed in flower.<\/figcaption><\/figure>\n\n\n\n
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Orange hawkweed flower detail. <\/figcaption><\/figure>\n\n\n\n
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Yellow hawkweed in flower by the roadside with other weeds. <\/figcaption><\/figure>\n\n\n\n
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Hawkweed leaf detail.<\/figcaption><\/figure>\n<\/figure>\n\n\n\n

Habitat<\/strong><\/h3>\n\n\n\n

Hawkweeds prefer full sun or partial shade and soil that is well\u2010drained, coarse\u2010textured, and moderately low in organic matter. They are mostly found on roadsides and in fields, pastures, and mountain meadows. Hawkweeds tolerate some shade and can grow in forest openings and cleared areas. Orange hawkweed is commonly found in or near residential yards and garden areas where it escapes from intentional plantings or as part of a \u201cwildflower meadow mix.\u201d<\/p>\n\n\n\n

Reproduction & Spread<\/strong><\/h3>\n\n\n\n

There are both annual and perennial hawkweeds. Annuals are spread by seed. Perennials also reproduce by seed as well as vegetatively. Some hawkweeds can reproduce vegetatively by runners, also known as stolons, which are above-ground stems. Hawkweeds can also produce viable seed without pollination. For most hawkweed species, flowering typically starts in late May or early June. Usually, some plants go to seed starting in July but plants continue to flower and go to seed through September. As a result of prolific seed and stolon production each season, hawkweeds are successful competitors, crowding out native, ornamental, pasture, and crop species.<\/p>\n\n\n\n

Redeeming qualities<\/strong><\/h3>\n\n\n\n

Flowers are visited by a variety of insects, including bees and butterflies. Also, leaves are nutritious for livestock, though trichomes (hairs on the leaves) limit animals’ desire to eat them. Plants can prevent soil erosion. They were originally introduced to the United States from Europe as ornamentals.<\/p>\n\n\n\n

Control<\/strong><\/h3>\n\n\n\n

No single management practice can be implemented just once to manage hawkweed. Ultimately, the management of hawkweed will depend on a program that integrates multiple procedures that increase the competitive ability of desired species of grass such as removing the hawkweed and adjusting the soil fertility.<\/p>\n\n\n\n

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  1. Test soil<\/strong> to find out what soil nutrients are deficient. Contact the Analytical Lab and Maine Soil Testing Service<\/a> for soil testing information.<\/li>\n\n\n\n
  2. Soil nutrients need to be added<\/strong> to encourage grass to outcompete hawkweed. Spread soil nutrients as needed on the whole lawn. (lime, fertilizer, compost, etc.) Refer to Bulletin #2154, Fertilizing a Home Lawn in Maine<\/a> for details about when and how to fertilize your lawn. In areas of bare soil, where hawkweed was removed, till or mix soil nutrients into the soil. Spread seed on bare soil areas, lightly rake, and firm soil. Keep moist if possible until new grass comes in. Endophyte-enhanced perennial ryegrass seed can be used to fill any bare spots quickly in lawns (not recommended for pastures or hayland).<\/li>\n\n\n\n
  3. Remove Hawkweed<\/strong>\n