These weeds find their place mostly in my flower beds. They are all perennial weeds that have deep, creeping roots or underground stems that help them spread with great speed.
Every now and then I go there to cut the grass two metres away along the fence and weed the Bindweed that climbs my fence.
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Aegopodium podagraria L., Ground Elder. This is considered one of the most invasive weeds that spreads itself by creeping rhizomes. The tiniest piece of it will produce new plant, followed by many more. Removing the leaves and stems regularly will somewhat weaken the plant. I usually remove the rhizomes by fork part of my hoe to avoid cutting them into smaller pieces. Sometimes I take out all the plants from the bed, do a deep soil cultivation trying to take out as many rhizomes as I can and re-plant the bed. The rhizomes are white in colour and easily to recognize. The plant itself is actually nice and there are also cultivars with variegated leaves. But it is only good for areas where we want a single plant ground cover because this extremely invasive plant will crow out all other plants.
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My neighbour has an imported species of plant in his garden - Polygonum japonicum, Japanese Knotweed. In many Europe countries it escaped the gardens and infested the land. So it happens in Croatia too. In my town, we have it mostly growing on wasteland and on the river bank. My neighbour does not live here and comes every now and then to check his yard. I am afraid if he does not try to eradicate it, it will come to my plot too. It spreads itself by rhizomes that are very strong. I read the story about the rhizomes finding its way into a living room!! It can grow from the smallest part of the rhizome and there is no other way to remove it but to spray with herbicides - year after year!