Discoqueen - it's an elder bush. Sambucus nigra - a very common self sowing native. You will need to cut it right down and then, if you can't dig out the roots, apply some sort of brush killer to the stumps. Before anyone says, why destroy an edible, these things are native here and sprout all over the place. They are a bit too common and a bit too large to tolerate in our small gardens.

The leaves and wood of elder have a somewhat unpleasant smell, which is easy to check for. And, as the link info says - the stems are hollow. Fairly easy to remove as it is not deep-rooting, though the roots do spread widely. Better to remove it entirely as it will resprout from the stump. If there are other elders nearby you are guaranteed more because the birds will bring seeds to your garden. Makes an 'interesting' jam from the black berries teamed with apples. Sort of a strong toffee flavour. (I don't think it was my jam-making...;-) )

Black Medic, a member of the clover (legume) family that grows best in compacted soils with low levels of organic matter. Short term controls are spraying with plant poisons while long term control is achieved by correcting the soil conditions that it likes to grow in. Start with a soil test for soil pH and major nutrient levels and then dig in with these simple soil tests to see what else needs be done. 1) Soil test for organic material. From that soil sample put enough of the rest to make a 4 inch level in a clear 1 quart jar, with a tight fitting lid. Fill that jar with water and replace the lid, tightly. Shake the jar vigorously and then let it stand for 24 hours. Your soil will settle out according to soil particle size and weight. For example, a good loam will have about 1-3/4 inch (about 45%) of sand on the bottom. about 1 inch (about 25%) of silt next, about 1 inch (25%) of clay above that, and about 1/4 inch (about 5%) of organic matter on the top. 2) Drainage. Dig a hole 1 foot square and 1 foot deep and fill that with water. After that water drains away refill the hole with more water and time how long it takes that to drain away. Anything less than 2 hours and your soil drains’ too quickly and needs more organic matter to slow that drainage down. Anything over 6 hours and the soil drains too slowly and needs lots of organic matter to speed it up. 3) Tilth. Take a handful of your slightly damp soil and squeeze it tightly. When the pressure is released the soil should hold together in that clump, but when poked with a finger that clump should fall apart. 4) Smell. What does your soil smell like? A pleasant, rich earthy odor? Putrid, offensive, repugnant odor? The more organic matter in your soil the more active the soil bacteria will be and the nicer your soil will smell, to a point. Too much organic matter can be bad as well. 5) Life. How many earthworms per shovel full were there? 5 or more indicates a pretty healthy soil. Fewer than 5, according to the Natural Resources Conservation Service, indicates a soil that is not healthy.

Thank you! They are very easy to pull, but I just wondered if I was wasting my time because they are so prevalent throughout my yard. Do you know if mowing them stops them from flowering/seeding? The mowers came so now they are very hidden/short.