The prior fall, we had cut and treated the knotweed (injecting about 5 cc of 25% active glyphosate solution into the remaining inch or so of each cut stalk). Our wetlands person came over to walk around and survey the results. The stand had been significantly weakened. For instance, you could walk through it. Previously, that had been impossible, due to its density. Progress had been made. Still, we knew we had a ways to go. You don’t just get rid of a huge knotweed patch in a year or two, you’ve got to stay after it.
Month: May 2015
April 2012 – Digging Knotweed Rhizomes
There was one area in particular, that seemed to have such a high concentration of huge rhizomes, that I actually used the backhoe. This is NOT something I’d necessarily recommend. Why? Because you have to be really careful about breaking the rhizome into little pieces; then if you miss taking up those little fragments, they will resprout into monster plants.
The backhoe was useful, because there were giant rhizomes around giant boulders underground. They were not going to come out with a shovel. However, I sorted through each and every bucketful of dirt, filtering out as many fragments as possible.
How many rhizomes did we dig out of that area? The following photos will give you an idea:
April 2012 – Straw is Still Paying Benefits
A photo of the “knotweed” area of the slope, from April, 2012. The straw is still helping to suppress the low perennial type of invasives, such as Euphorbia cyparissias (“cypress spurge”), which is rampant on the slope. While tiny, it’s still very difficult to get rid of. It’s listed as “likely invasive” on the MA invasive plant list.
Some low, nuisance plants seen in the above photo:
- Lepidium campestre – “field pepperweed,” was ubiquitous. This particular plant is not on the MA invasive plant list, however, Lepidium latifolium, “tall pepperweed,” is. Still, field pepperweed is not native, and will take over, given the chance.
- Tanacetum vulgare – “common tansy,” in lower left corner, is another aggressive perennial on our site, and is hard to get rid of. Constant mowing in the back acre takes care of it. We don’t mow the slope, so we’re constantly pulling it out. (A different plant, Senecio jacobaea, “Tansy ragwort,” or “stinking Willie” is listed as likely invasive in MA)
- Verbascum thapsus – “common mullein” in middle right, is a perennial herb. In its first year, it forms a low rosette that sort of looks like lamb’s ears. There are always a few around the slope, however, they haven’t ever become a problem. I’ve just let them be mostly; sometimes we pull them out.
The First Order of Dozens of Trees and Shrubs
We purchased dozens of baby trees and shrubs. If they’re babies, they’re affordable. We did splurge on twenty quart-sized Green Giant arborvitaes and three “whip” Princeton elm trees (a newer cultivar, resistant to Dutch elm disease). We placed our order in January, 2012, to be delivered in April. I had no idea of how I was going to get all this stuff planted, but at least we had a tractor!
10 River Birch (Betula nigra) – 2-yr seedlings
10 Silky dogwood (Cornus amomum) – for wildlife
10 American Elderberry (Sambucus canadensis) – for deer
10 Pieris japonica ‘Scarlet O’Hara’ – for the front yard
25 “Sandy” rosa rugosa – to plant over where knotweed was
10 Royal Purple Smokebush – (cotinus coggygria)
10 Weeping Willow (salix spp.) – for the back acre
10 Nigra Pyramidal Arborvitae (thuja occidentalis “nigra”)
10 Rheingold Globe Arborvitae (thuja occidentalis “rheingold”)
10 Sherwood Frost Pyramidal Arborvitae (Thuja occidentalis)
10 Blue Chip Juniper (Juniperus horizontalis) – for the slope
10 Blue Star Juniper (Juniperus squamata) – for the slope
10 Old Gold Juniper (Juniperus chinensis) – for the slope
10 Black-eyed Susan (rudbeckia fulgida “Goldsturm”)
10 Purple Coneflower (echinacea purpurea)
20 Dragon’s Blood sedum (sedum spurium) – for septic field
15 Grass (festuca glauca “Elijah Blue”) – for septic field
February 2012 – The Straw Idea Worked
Here’s what the “knotweed” area of the slope looked like, toward the end of winter, 2012.
The phragmites, having been treated the autumn prior, were dead, and now it was our task to remove their huge biomass. The H.S. football players came over to help us cut the dead phragmites stalks, then drag them onto a brush pile for later burning.
Inspiration from Maine
Straw, Straw and More Straw
You can never have enough straw. Here’s a closer-up photo. The straw helped prevent erosion over the winter months, and also helped to subdue the sprouting of numerous ground-level invasives, which were sure to rear their ugly heads, now that we had removed much of the shrub layer.
The Nursery Area
We were lucky to have a friend with a greenhouse, who had lots of extra plants (trees!) he was trying to find homes for. We were the recipients of about 3 dozen baby tree lilacs, and around 10 baby Osage Orange trees (plus a number of magnolias and redbuds). We designated a nursery area, on the west side of our property. Here, we could easily keep an eye on things, and the hose reached over there as well.
We found a source for wood chips. You can never have enough wood chips. We covered our tractor with a tarp, and we covered the nursery area with straw, for the winter.
2011 Plants Acquired From Various Sources
1 Juniperus Chinensus “Blue Point” – next to where knotweed was
1 – Picea Pungens “Glauca” “baby blue” – spruce – #2, SW corner of pond
1 – Salix Purpurea “nana” Blue Arctic Willow – on E slope
1 – Ilex Meserveae “Honeymooners Holly” – front, NE corner
1 – juniperus horizontalis “blue chip” – for steeper part of slope
1 – Juniperus Squamata “Blue Star” – for stabilization of slope
1 – Azalea “Rosebud” – front, NE corner
35? – Syringa reticulata – tree lilac babies – in nursery area
3 – Cornus Alba “Elegantissima” – Red Twig Dogwoods – shadier slope area
1 – Cornus Alba “Elegantissima” – Red Twig Dogwood – front, NE corner
5 – Cercis canadensis – redbud trees – nursery area, E side of house
1 – Magnolia Stellata – magnolia
1 – Magnolia Soulangeana (“Leonard Messel”) saucer magnolia
1 – Magnolia Loebneri – magnolia
1 – Magnolia Encore – (might be the same as loebneri or star)
The Black Tarp and Vaccinium corymbosum
Smack dab in the middle of the slope, lived a particularly pernicious mass of knotweed rhizomes. We had been trying to cut it back for a couple of years, we tried to dig out as much as we could, however, none of that seemed to be working. Finally, I took a big black tarp, and just covered it up. I weighted down the tarp around its edges and a little of its middle. I didn’t want to cover the whole thing because I wanted the sun to make it as hot as possible.
This tarp was there for quite a while, but it did the trick!
