Part IV - Living Walls - Borders & Hedges: Yews and Hemlocks
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- Marge_Talt
- anewleaf
- Marge_Talt
- anewleaf
- Marge_Talt
- washingtonarms
- Marge_Talt
- MommaLibrarian
- anewleaf
- valliygirl
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» Marge_Talt - Re: Hemlock in these times?
In response to message posted by anewleaf:Hi anewleaf, Welcome to Gardening in Shade!
The hemlock wooley adelgid is an issue, no question about it. I have found, however, that timely applications of horticultural oil work just fine. It would be impossible to spray a fully grown, unpruned specimen without special gear and probably access to a cherry picker, but I can deal with my hedge and weeping specimen easily.
You do have to keep a sharp eye on your plants and deal with the pest when you see signs of it.
You are correct about recommending hemlocks because of this, but with this caveat, and the willingness to monitor the plants, they still are sometimes the best solution for a particular situation.
It is such a pity about the wild stands because there is really nothing that foresters can do about it - there are just too many huge trees. I don't know if work is being done on bio controls, but I sure hope so...but bio control programs are a long, long time in the testing before they can be implemented and it may be too late for our native trees:-(
-- posted by Marge_Talt
» anewleaf - Re: Re: Hemlock in these times?
In response to message posted by Marge_Talt:No bios known yet. But another chemical you can use is Imidacloprid. it is a bayer exclusive....in the tree and shrub insect control product. this is the same chemical as Marathon used in the greenhouse industry for whiteflies and fungus gnats and Merit used in the nursery industry for sucking insects...like adelgids, which are little more than living guts.
Application on large(all) specimens is simplified by the fact that it is applied to the soil under the tree, in the root zone in a water mix. one application in spring is good for a year. At first glance it seems a bit pricey, but considering its longevity its a pretty good deal.
The adelgids mode of attack is a bit curious. Typically the first attack is heavy and then nearly disappears as the hemlock responds with natural defences. Often a homeowner thinks they have weathered the storm- false security, I'm affraid. The few survivors tho are immune to the tree's defenses and wham, bam.... the second wave pretty much finishes the job on the weakened tree.
So far, my observations are that the imidacloprid seems to be effective as a repeat agent, but one can't rule out the possibility of adelgids developing resistance over time...so the best course seems to be to use it sparingly...once every two, three, or four years, which really ought to be effective.
-- posted by anewleaf
» Marge_Talt - Re: Imidacloprid for woolly adelgids was:Hemlock in these times?
In response to message posted by anewleaf:I've read about Imidacloprid being used against vine weevils, but didn't know it was effective for woolly adelgids..thanks for the info.
It appears that of the many products containing it, 3 forumlations of Merit are the only ones listed for use as foliar sprays or soil drenches for this pest. Which of these would you recommend? I normally stick to hort. oil and Safer's so have virtually no experience using the more heavy duty pesticides.
Just did a bit of a search on it. E X T O X N E T has a detailed explanation of potential hazards in using products containing it as well as product names. It appears it is toxic to bees, so care needs to be taken in using it as a foliar spray. also appears to affect some ground feeding birds.
I found your explanation of how these dratted pests attack hemlocks most informative...thanks for posting it.
-- posted by Marge_Talt
» anewleaf - Re: Re: Imidacloprid for woolly adelgids was:Hemlock in these ti
In response to message posted by Marge_Talt:For use as a soil drench on woodys, the wettable or soluable powders would be preferred. A very small container (Aspirin bottle size) of merit which is a highly concentrated nursery formulation is very expensive but will go a very long way. The average homeowner should purchase Bayer Tree and Shrub Insect Control. Even then you are looking at somewheres around 20 to 25 bucks a container. It is dilute, I believe something on the order of .18% active....but don't quote me on that. A single container will do a large tree to several shrubs. It is applied by mixing it in a watercan and sprinkling in the root zone.
Using this method should afford little hazzard to bees, (unless one has a yellow jacket nesst in the ground where it is applied) and i would suspect the hazzard to birds would be minimal. The studies cited at Cornell adress feeding on treated seed, which most likely would provide a high dose and apparently when not force fed, birds are inclined to leave treated seed alone due to gastointestonal stress, which must occur rapidly for the birds to assocoiate the retching with the seed.
Any chemical needs to be used with eye towards off target effects and with reason. This one looks to be safe when used according to label direction. Again, with a product such as this one application is active for a season, and likely won't be needed every season, thus reducing the propensity for over exposure in the environment.
There is nothing more noble in the east than a grove of mature hemlocks....It is a unique experience to walk into one.... a feeling of forest primeval. It will be a shame to effectively lose yet another of our native eastern forest denizens. While it will require effort to maintain them in the landscape...even as shorn hedges...it will be well worthwhile if they do no more than elicit memories of what once was, just as a few olde timers share with us today memories of what a noble tree the American chestnut was.... often stimulated to do so by a struggling chestnut sprout emerging from an anchient root.
-- posted by anewleaf
» Marge_Talt - Re: Imidacloprid for woolly adelgids was:Hemlock in these ti
In response to message posted by anewleaf:Thanks for all this info. I shall save it as there may come a day when my hort oil is not doing the trick and I have to fork out that kind of cash.
Unless some bio-control is developed, I fear all of us growing hemlocks are going to need to be vigilent and continue to treat for these pests.
I've never walked in a mature grove of hemlock, but can imagine it would be quite an experience.
They are such graceful trees. Even clipped as hedges, they are still graceful as their new growth tends to soften the outline, if you know what I mean. Plus, they are nice to work around, having very soft needles, unlike, say spruce or deodor cedar, whose needles are prickly as all get out.
I sure hope we don't end up losing our native stands.
-- posted by Marge_Talt
» washingtonarms - Any suggestions for evergreen ground cover?
Marge,You've been so helpful in the past, I was hoping you could help me out with another project...
I'm helping my mother-in-law with some landscaping, and was trying to find an evergreen ground cover for an area of her backyard that is about 20' by 20' under a large maple tree (so it gets a lot of shade, but some light gets through at different times of the day). The area is never flooded and never has standing water, but it is almost always muddy. I was looking to plant something like pachysandra or ivy. Do you think they will grow in these conditions, or do you have any other suggestions?
Right now, it is mainly brush and weeds, with some skunk cabbage. The home is located in the Pocono area, in northeastern Pennsylvania (which puts it right on the border of zones 6 & 7).
Thanks!
-- posted by washingtonarms
» Marge_Talt - Re: Any suggestions for evergreen ground cover?
In response to message posted by washingtonarms:Well, if there's skunk cabbage growing there, you have a naturally boggy site - probably an underground spring of some type...am I jealous! I've wanted some skunk cabbage for years; been trying to germinate seeds, to no avail...sigh.
Anyway, Pachysandra and ivy will not do well in boggy conditions. I would NOT remove the skunk cabbage, but put in more damp loving plants to go with it. While I don't think skunk cabbage is endangered, it is relatively rare and should not be destroyed if possible.
Evergreen might be a bit tough in a groundcover tho' there are evergreen plants that are clump forming that love just those conditions.
Acorus gramineus 'Ogon' flourishes in boggy conditions as well as regular borders and is rated hardy to z5. There's also Acorus gramineus 'Variegata' - a white variegated form, where 'Ogon'is gold variegated - very neat, low plant that will spread in time. Both are evergreen and 'Ogon' (the one I grow) always comes through winter looking good for me.
Houttuynia cordata 'Chameleon' (z4) is not evergreen, but will take over the world in a damp condition and make a very thick groundcover during the growing season - very attractive plant that I hesitate to recommend for border use, but if you want to have something maintenance free that covers ground from mid spring until frost, this is it.
Lysimachia nummularia (z4) will also cover ground in damp soil - it is not evergreen, but wakes up early in spring and stays through until the worst frosts. The yellow form, 'Aurea' is really nice, tho' it will be more chartreuse in shade.
The candalabra primroses, Primula japonica, Primula Beesiana, and Primula Bulleyana would love that kind of spot. Again, they aren't evergreen, but they grow fast once spring starts and get huge as cabbages. They seed around heavily and will cover large patches of damp ground in a few years. Not only that, they have marvelous flowers. Their foliage gets about 18" (45cm)tall and their flower spikes up to 2'(60cm).
There are other large and small plants that would do well in this type of location, but they aren't exactly ground covering except for Petasites, japonicus giganteus and that's so incredibly rampant, I'd think twice about it in an unconfined location.
Personally, if I were blessed with a naturally boggy spot, I would use it to make a garden of bog loving plants and count myself really lucky. I have to make boggy or damp places - a whale of a lot of work. There are so many incredible plants that demand constantly wet soil!
If you think your MIL would want a garden there, instead of just a groundcover, I can list a few more that would grow in such a spot - taller plants that flower or have grand foliage or both plus sedges...oh, there are so many. My damp bed is now overflowing; I could use 4 times the area and still wish I had more wet soil:-)
-- posted by Marge_Talt
» MommaLibrarian - high border
I live in zone 5 about 15' down and 40' away. I have a strip of east facing, amended clay soil under a mature black locust which I would like to plant with something with an attractive trunk and leaves starting 6 to 10' off the ground. If I lived further south Crapemyrtle would be the perfect solution. Do you have any ideas in my climate?-- posted by MommaLibrarian
» anewleaf - Re: high border
In response to high border posted by MommaLibrarian:
Obviously Marge has been outed by the new regime.... a shame this site has gone totally commercial. Another good reason to avoid it. I post on gardenguides these days. Go to gardenguides.com post a question in the forum and I or our many other gardening friends there will be happy offer suggestions.
-- posted by anewleaf
» valliygirl - Trimming Hedges
Hello all,Recently I have been volunteered to trim hedges at a friends house. The home is a new purchase and the juniper hedges have been obviously left unattended for years.
In some places they are 12-13 feet high and in one spot need to be cut fully away from the driveway so backing out is safe(About 5 feet). Need to be reshaped and in some cases drastic cut backs are needed.
I have been reading online to locate the best way to do this but all the sites indicate just a drastic cutting back may cause these hedges to die off, and turn brown. Help.
-- posted by valliygirl
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