Vigorous, Aggressive or Invasive?

One of the tips I gave while lecturing is to try to read between the lines when reading that tag in the pot at the nursery. The advertising world is a savvy one and many descriptions are phrased to make something that's not very desirable look perfectly normal or even an asset.

Two phrases get me hot under the collar. The first is when the tag says "short lived perennial". Reading between the lines, that usually means the plant is a biennial. Why not just say "will die right after blooming". I have many biennials that I grow and adore but at least I know they're supposed to only live two years and I don't fret and wonder what I did wrong that killed the poor thing.

The second phrase that drives me crazy is "vigorous grower". When you see this phrase it usually means "start running after you've planted me in the ground if you don't want me to bury you alive". So often I'll be shopping at a plant center and see people pick the pot that's busting out of it's seams. "Look Honey, this one even has some pieces growing out of the drainage holes, what a great bargain!". I want to tap them on the shoulder and say "start running now".

Being realistic, when does a plant cross the line of vigorous to aggressive or worst of all, invasive? I don't care about whether it's a native plant or an import, invasive means invasive. It means that the plant will run over, through, or under all neighboring plant material. In a few cases it might be the seedlings that self sow in the middle of other plant material but most often it's the underground thugs that I've got a problem with.

Lysimachia ciliata 'Firecracker' is the number one thug in my garden today. I can only blame myself for this one. A good gardening friend shared a piece with me and warned me that it runs. I fell so in love with the rich purple foliage that I begged more pieces from her.

The above two photos are two viewpoints of one planting area. The first shows you how lovely the purple foliage contrasted with the neighboring plants. The second photo shows you more of the surrounding area, the Lysimachia still fairly well clumped with a few stray pieces off to the left.

When removing leaves from this area in the last few days I'm horrified to see that the Lysimachia is everywhere, choking out the daylily clumps like they were butter. The Nepeta 'Six Hills Giant' and Euphorbia are still holding ground but for how long?

The little blue ground cover here, Mazus reptans can run as far and as fast as the Lysimachia ciliata. The big difference is the Mazus doesn't choke the companion plants. It simply grows around them and fills in any open spots. If it goes where I don't want it, the roots are extremely shallow and I can remove any unwanted plants in a few minutes.

Here in this golden yellow display are several vigorous growers. Coreopsis 'Zagreb' is the strongest growing Coreopsis in my garden. I choose it over other varieties because it never flops, the stems nice and strong. While it might not grow through a daylily clump, it spreads at a good rate and every 4 years or so I need to go in and pull back the outer edges.

The large leaves in this photo are from the perennial Begonia, I don't have a better name as it was a pass along plant. I'm not sure it's as perennial as people tell me, it just might be a good seeding annual but it has never sown too many plants for me. Further up in the photo though is the adorable blooms of Corydalis. While I'm crazy about this plant, I really need to get in there and be ruthless with some of those seedlings. At least they are easy to pull out.

Uh oh, do you see what I see? There's that tiny spot of purple in the left hand margin. Guess what's run over, through and under everything in this area now?

While most Sedums are well behaved, there are a few that are vigorous growers and yes, some are invasive. This photo shows Sedum aizoon 'Lemon Snowflakes'. It's not invasive but I would list it as vigorous. The original clump grows at a nice pace but it sneaks out seedlings that pop up in the general vicinity. Thankfully it is so pretty and so few people grow it that I've found homes for all those seedlings.

The very first Nepeta I ever bought was at a local nursery named Franks. I didn't know anything about cat mints, didn't save the tag either but the name Nepeta mussinnii keeps popping up in my head. This plant seeds around all over but never choked out another plant. Best of all, I've put many of it's babies in large planters and they over winter just fine. They have such a long bloom season and look so lovely cascading about that I still wish I had more of them.

If you look carefully though you will also see the foliage of Violets in this bed. They are a bit harder to deal with and would have to be moved up the list at least to "agressive" and I know other people who would call them "invasive". It took a bit of practice but now when I weed this area I use a dandelion fork and pop out any violets that are in the middle of the dwarf Hosta.

Symphytum (comfrey) was on my wish list for years. The only variety I've found for sale is this pink one, 'Langham's Pink'. While I was highly warned by others, I bought five pots of this plant. Contrary to all advice, four years later they are still in clumps, not a runner or seedling to be found. I'd really like to try to divide these beauties up in a few weeks.

When it comes to finding out what plants are vigorous, aggressive or invasive, blogging just might be the best available tool. While there are plenty of great gardening books out there with this information, it might take you hours or days to find what you need to know. By going to the search tool at Blotanical, you can simply type in a plant name and instantly read about how it does in other gardens. Pretty cool! If only I had thought of that before I twisted Chris's arm for more Lysimachia...

And now for the most distasteful task of all, time to empty the hearth and fireplace of all winter decorations. Other people might call those decorations "Christmas" decorations but thankfully we call them "winter" decorations so we can leave them up all winter. For the past month I've been averting my eyes every time I walk through the living room. It's a much hated job since it requires numerous trips up and down the attic stairs while loaded down with boxes. That's my ugly confession for the day.