Thursday, June 6, 2013

Discovering My Invasives

As we are coming into late spring and I have been marveling about all the native plants I have found a crop of invasive plants has manifested themselves.  I know some of these were lurking out there, others were plants that I had misidentified, but have now reveled themselves now that they are in bloom.  Here a run down on what I've got, but wish I hadn't, and I plan to do about it.

Multiflora Rose, Rosa multiflora, is scattered around the property, mostly in the woodland edges.  These roses can be identified by their frilly stipules (leafy appendages at the base of the petioles), but now are very obvious by the clusters of fragrant, small white flowers.  I had hoped that I had some native roses out in the field, but so far it looks like they are all Multifloras.

Left to its own Multiflora Rose will send stems high into a tree.  
For the plants out in the open I am continuing to mow over them.  For the more established plants I will cut and treat the stumps with concentrated Round-Up in August.  I will do an earlier cut on some plants to prevent this crop of seeds from maturing, but I want to leave enough for easy application of the herbicide later in the season.

It turns out that a couple of small trees that I thought were Pin Cherries are actually Autumn Olives, Elaeagnus umbellata.  My mistake was made clear at the beginning of May when these plants were coming into full bloom.  I was drawn to the wonderful sweet scent.  When I saw the flowers I realized that what I had was definitely not a cherry of any kind.

These two Autumn Olives are nicely situated on either side of a path.
I'll cut them down soon and replace with something native,
maybe Winterberry Holly and Tupelo

These fragrant tubular flowers
were very popular with the bees.

I decided to let these finish flowering before cutting them back to a stump and then treating the fresh cuts with Round-Up concentrate.  This seems to be a pretty general method for killing undesired shrubby vegetation.  I did this to a very large Euonymus alatus in mid-March and I have seen very little if any regrowth so far this season.

When we first moved in last fall I noticed a lot of honeysuckle vines growing everywhere.  I had hoped that they were the native Coral Honeysuckle, Lonicera sempervirens.  There were no berries present (Japanese Honeysuckle has black berries, L. sempervirens has red berries) so I couldn't tell by that.  Also a cross section of the stem appeared to solid, not hollow, so I assumed it wasn't Japanese Honeysuckle.  Now that they are coming into bloom with their sweet-smelling white flowers, I see that I have a lot of the invasive honeysuckle.  A check of the stem shows that these are in fact hollow, so looking at the cross-section of the stem may not be a great late season indicator for this species.

Japanese Honeysuckle flowers start off white, then turn yellow after a couple of days.

I'm not sure what approach to take on all the trailing stems on the ground.  Pulling and late season herbicide applications can be effective (as long as the leaves are still photosynthesizing).  In the interim I have been cutting the stems of the vines up in the trees to minimize seed production.

Garlic Mustard, Alliaria petiolata, is well establish in the wooded areas on and around our property.  I am trying to remove all of it from an area before moving on to a new area.  This is a more effective strategy for elimination than just pulling a few plants here and there from a much wider space.  The seed heads are just about to mature so it's time to take a break from pulling.  If you are pulling plants that are shedding seeds, it's kind of like planting more of them.

Year old rosettes of Garlic Mustard remain green here over the winter.  This gives me the option of either pulling or spraying when most of native plants are dormant.  Because of the diversity of native plants in the woods, I will continue pulling up any Garlic Mustard I see each spring and fall.  this will be a multi-year effort.
Same area after clearing.  The ground plane is now opened up.

Note the white center vein on the leaf.
Japanese Stilt Grass is wide spread in this area.  It fills in shady borders with a dense mass that can smoother out other plants.

As an annual it can be controlled if you can keep it from going to seed.  Cutting it back when it begins to flower in late summer can keep it from successfully setting seed.  Cutting it back earlier may stimulate earlier flowering.  For plants in the woods I will go after them with the weed wackier in August. This grass has a weak root system and is easily pulled up, but there is just so much!

This is a very leafy grass and is soft to the touch.  The shiny mid-rib is a feature that sets it apart from other grasses

This is a recently opened-up area where the stilt grass is going to town.
It is joined by some garlic mustard and  bittersweet.
The near-by poison ivy is slowing my progress here.

Note the triangular leaves of Mile-a-minute vine.
There are nasty thorns forming on all  parts of this vine.

Mile-a-Minute Vine is a very fast growing invasive.  Once I noticed it I took some time out from writing this post to pull it out right away.  It is really important to do this before its many thorns begin to harden.  In my enthusiasm I accidentally pulled up a new Redbud tree, because its heart-shaped leaves looked similar to the triangular leaves of Mile-a-minute.

To combat this invasive, a weevil has been introduced and has been found to be very effective, and selective, at consuming this plant.  I examined the plants I pulled but saw no signs of this insect.  

To keep from going crazy I've realized that these invasives did not appear overnight and that any reasonable action is a step in the right direction.

1 comment:

Laurrie said...

I have been doing the same battle against multiflora rose and autumn olive (also bittersweet) which is all around us in great and overwhelming abundance -- using round up on cut stems, etc. I really hope you can keep at it and make progress!

I have lost the battle, and now all I try to do is get the rose canes and bittersweet vines off the youngest trees. The garlic mustard and mile a minute vines go crazy here. We have so much untended "wild" area around us, with subdivisions artfully built in among the "meadows" and trees and fields, that the battle is impossible. Here's hoping you can get at what is near you and control it better than I have : )