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It comes up in the spring, gets about 3.5 ft tall, never blooms & dies back in winter. I've pulled up a lot of it; it grows from an underground thick runner type root system. I think it's a general weed, but want to be sure before I kill it all. I'm trying to eliminate invasives and encourage natives on the property. PairedLeaf

Close-up of top click here.

EDIT: Jul 22, 2014 - It is dog bane, a/k/a indian hemp with buds. It did "bud up" and finally bloomed but not large flowers, just barely open little bell-shaped blooms. See also bottom right link on this page; branching near top, somewhat reddish stems. Dogbane is a nectar source for adult monarchs (and many others), but NOT host plant for the monarch caterpillar. It is hosting an unidentified communal web that produces a small green, becoming a fuzzy white caterpillar (growing larger over a couple weeks). I have not seen a cocoon to know what, if anything, it becomes.

2 Answers 2

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Milkweed.
You can positively id this species by breaking a leaf. Sticky white sap will come from the break.

This plant could be asclepias tuberosa which is native or poke milkweed, Asclepias exaltata, which is also native but you probably don't want in your garden as it is a bit invasive.

The leaves seem a bit narrow for the common milkweed which is native and you definitely don't want in your garden. This is the only perennial I have seen send roots six feet out under flagstone to find a place to sprout.

Edit: GDD mentions that it has never bloomed. It looks like this is planted under the eaves of a house. This area could be dry and shady which is tough for any plant. The conditions needed to flower are lots of sun. It does not transplant well due to the extensive tap root system. You should consider planting named species in a better location to get flowers if this location lacks sun.

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  • I hope you're right about it being one of the milkweeds, but it's never bloomed! No white sap in leaves, but there is in stem. I'm creating several areas as butterfly/hummingbird refuge and bought A. incarnata, A.tuberosa, A.syriaca, and even A.hirtella seeds for fall planting, but have never seen milkweed leaves. Maybe it needs more water to bloom?
    – GDD
    May 30, 2014 at 21:02
  • Try less nitrogen. Nitrogen will promote vegetative growth, less nitrogen in proportion to the other two macronutrients, P and K, will promote blooms...is this planter near the lawn?
    – stormy
    May 31, 2014 at 1:18
  • Yes, @kevinsky they're growing very near the mostly west facing house, some are under the eaves. Full sun, no lawn. They do look like they're putting out buds at the top since I've started working that area (dividing & re-planting spring bulbs). That's when I discovered the extensive "rhizome" root system. This wasn't one of the planned butterfly areas but I can be flexible! I am accepting this answer.
    – GDD
    May 31, 2014 at 10:40
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The easiest way to get rid of weeds like this is to 'starve' them. You do this by cutting them off at the base, no photosynthetic growth, no root storage. It'll take a few years but works well. I've done this with blackberries, horsetail and Japanese Knotweed. You can also try glyphosate while they are green and healthy to subdue the roots. Spray carefully or wet chemical resistant gloves and wipe onto the foliage. Leave alone for 2-3 weeks, then start your chopping campaign.

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  • Agree with 'starving' @stormy by eliminating greenery to eventually kill roots. I'm trying to avoid glyphosate. If this is really milkweed though, I want it.
    – GDD
    May 30, 2014 at 20:49
  • This is a pretty and healthy looking plant, isn't it! I have a bottle of roundup I've never used but I have to say it is a pretty safe herbicide used correctly. I remember some guy giving a seminar who said, "you can practically drink this stuff..." Well forget THAT!! Doesn't leach, changes chemical composition as soon as it is sprayed and won't accumulate. Whatever. I agree that just starving them is enough, takes a bit longer is all. Great for graveled areas, if you can stand looking at dead/dying weeds for 3 weeks. Good for reducing vigor of roots.
    – stormy
    May 31, 2014 at 0:25

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