Burcucumber Sicyos angulatus L.
Family: Cucurbitaceae (Gourd family)
Life cycle: Annual
Native status: Native to N. America
Habitat: Crop fields; fencerows; treelines; waste areas
General description: Vine reaching lengths of 10 ft. Stems are sticky hairy and ridged, tendrils facilitate climbing. Leaves are round to heart-shaped, up to 8” long with 3-5 shallow lobes, pointed tip, and dentate margin. Flowers are small, greenish-white; fruit are oval to elliptic, up to ¾ in long, pointed at tip, and covered with stiff bristles and numerous hairs. Fruit are arranged in clusters of 3 to 10 individual bur-like seeds. Plants capable of climbing and totally covering trees, fences, etc.
Key ID traits: Vine with sticky stem and long tendrils; leaves up to 8 in wide and long with shallow lobes. Clusters of pointed fruit with stiff bristles.
Similar species: Wild cucumber has a similar growth habit, but the leaves are more deeply lobed, resembling a five-pointed star. The fruit of wild cucumber resembles a small cucumber (< 2 in) with stiff spines. Wild cucumber is less likely to move into crop fields than burcucumber.
Miscellaneous: Burcucumber is one of the most troublesome weeds in agronomic crops because it germinates throughout the season and is capable of rendering acrop unharvestable. Plants that emerge after postemergence herbicide application are still capable of climbing crops. It has been said that when harvesting a soybean field infested with burcucumber all you need to do is pull the combine into the field, turn on the reel, and the entire crop will be pulled to the combine. Fortunately the plant produces a relatively small number of seed, thus a large seedbank isn't produced and with concentrated efforts the field can be cleaned up in a few years. Many people think it should be listed as a noxious weed in Iowa because of the difficulty in managing it, but noxious weeds typically are exotic species, not native.