Agastache: The worst weed in my garden!

Last year I started a whole bunch of perennials from seed for a butterfly/hummingbird garden. Agastache foeniculum ("Blue Spike" anise hyssop) was one of them. The plants grew well and bloomed that first year. I wasn't that crazy about the light lavender color so I've been wondering if I want to keep them.
WELL, let me tell you something- I made the mistake of letting these things go to seed and now they're popping up all over the place! They are, by far, the worst offender in my garden. Now I wonder if I'll ever get them all out!
In all of my research I don't remember seeing any mention of how invasive the seedlings can be. There's even an article about them in the June 2003 issue of "Garden Gate" magazine and it doesn't mention their prolific self-seeding. It says to propagate them by division!
I have half a mind to rip out the original plants (which are 4 feet tall this year!) just because I'm afraid I'll miss dead-heading one of the flower stalks before it spreads its seeds to my neighbor's garden.
Well, I just wanted to get that out of my system.
Doug in NJ.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I
I
them
tall
flower
I started some from seed about 4 years ago. I agree that they are prolific self-seeder. In the spring I have thousands of them appearing around the established plants and a few here and there a few yards away. I don't find them troublesome as I can just cultivate with a hoe or hand cultivator and the seedlings are eliminated. The variety that I have isn't very showy (licorice blue). It does attract a lot of bees and butterflies. I let it go to seed and leave it as-is all winter because it gives some interest to the garden. I also enjoy the fragrance of the foliage. I have several weeds that are far more troublesome: Virginia creeper, wild honeysuckle, wild strawberry, creeping Charlie, bind weed, thistles, onions, poke weed, and a very troublesome unidentified weed that spreads like crazy and produces clusters of small, dark pink flowers.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
dstvns said:

It's a type of smartweed or knotweed (Polygonum). Can't identify it more specifically than that.
--
Pat in Plymouth MI

Any technology distinguishable from magic is insufficiently advanced.
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

YES!!! That is the weed. I pull and pull and it keeps reappearing. It got established in a the bad that has astilbe. I didn't notice it for some time as the leaves tend to blend into the astilbe. Now it is in the lawn also. I have used Round-up and it just keep going.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Try this site for pictures of common weeds.
http://www.ipm.ucdavis.edu/PMG/weeds_common.html
Marvin & Sue
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

Looks like the common name is ladysthumb (Polygonum persicaria). Thanks very much,
Dan
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

I have many anise hyssop plants spread around. They are very beautiful, but they bloom during the same time as bergamot, so the hummers only use anise-hyssop very early in it's bloom time (ie just before bergamot blooms, one week in late june early july in nw NJ). Then they all fly over to bergamot.
The anise-hyssop seems to be spreading around, but I've let it continue to spread. The deer tend to wipe out new growth in early spring, so many plants never make it to the summer. It is a bee and butterfly magnet while in bloom, and I hope many people will think about planting this extremely easy-to-grow plant, which is also native to north america.
It is also considered a good honey plant for apiarists. Unfortunately, most apiarists up here are ruined due to bear problems. The bears tear through thousand-volt fences to get honey. Most beekeepers I knew don't even rebuild. Tens of thousands of dollars of equipment destroyed, the rest walking off in the black brute's belly. Good thing there's going to be a hunt this year.
Dan
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.