Last week I received some great advice about planting willow trees near a pond from some of you who obviously have great experience... so, just to let you know, we're taking your advice! Instead, we are getting about 16 spruce trees (vary in height from 20-40 feet) from one of our neighbors higher up the mountain. What do you think is the safety zone for planting those near the pond without endangering a betenite seal?
Secondly, our land is in a valley with a stream running through it. While the land is ours, the surface water is not (that is owned by all those people in AZ and CA - a long standing battle from Colorado ranchers). Anyway, the approx 30 acre feet of water WE own is in an aquafer 890 ft down and we pump it. Yes, we have tons of water to irrigate, but that is the only way to get it. Therefore, the pond must be filled from the well. Is there a minimum depth that affects evaporation but would also allow us to stock a few trout for the kids? (We are at 7000' elevation.)
And lastly, as this land is essentially on three levels, 1)the valley with stream, 2)our house level which is on a plateau about 15 ft above, and then 3)another rise 10' that slowly climbs about 300 ft over the rest of our land. We are planning on putting the pond on the house level (about 150 ft from the house) and thinking of using a rock lined spillway vs. a pipe to the valley below. Is that the best aprroach for a dig-out pond?
Sorry to ask so many questions at once... but you guys are obviously the experts!
I'll help with one question at a time. Betonite seal? Do you mean betonite, packed clay, or betonite mixed with soil seal??
1. Betonite seal will be your thinnest most sensitive and easiest penetrated seal.
2. Packed clay, depending on thickness should be your thickest, most durable seal. (6' to 8' thick is best)
3. Betonite-soil mix will be in between the above two. This will depend on the depth thickness of the mixing of bentonite into the soil or layers.
Betonite seals are sensitive to cracks/leakage due to water loss from evaporation.
If the original seal is "tight" the integrity is best maintained if the pond is kept full and the water level is not allowed to drop much.
I've seen 40' tall spruce tree roots spread out up to 25 feet from the tips of the branches.
I'll tackle two other concerns. If you use bentonite as a seal, that seal will be near the surface, to several inches below the surface. Tree roots won't bother the seal. To be safe, plant the trees far enough away from the pond to be sure the drip line never encroaches the area where your bentonite seal starts.
Second, you asked about a rock spillway or pipe.
If you intend to re-use the water, pipe it downhill, where you want to use it again. Rock spillways increase surface area of water contact with air, increasing evaporation. It may be a minimal impact, but when water is a precious commodity, every gallon counts, especially if it goes into a garden or the tummy of an animal.
I'm back to help with some other parts.
1. Depth will have little affect on the evaporation rate. Evaporation rate is enhanced by amount of exposed water surface, increased air temperature and increasaed wind speed.
2. The depth of your soils before you hit rock may predetermine your pond depth.
3. I disagreee somewhat with Bob about tree roots not affecting the betonite seal. They will have a big impact on the seal if they penetrate the seal. Also, I have seen roots extend WAY BEYOND the drip zone of the tree canopy. As much as three or fout times further than the drip zone. Some tree species can send roots farther out from the trunk than others. Amazing, and I would not have believed it unless I saw it. One inch dia roots embeded in pond wall that was 50' to 60' beyond the branches of large cottonwood trees.
A question back to Bob - Isn't a spillway just used when the pond is in overflow condition? I'm not sure why you put that together with water usage. And to both Bill and Bob, if betonite is used, to what height up the pond side should that go? Directly below the anticipated water level? If there were an embankment condition, couldn't that threaten the structural integrity of the dam area above the betonite line during overflow conditions?
Thanks for hanging in there with my questions!!!
gonna need some massive equipment to dig and move 20 to 40 ft. evergreens, good luck , let alone them live.
i have to agree with ken....20-40 foot trees will require lots of machinery, watering, nurturing, and moolaa!! consider a few year old trees and be patient. mark
I'm not sure I understand your 3rd question ..... theaten the structural integrity of the dam area above the bentonite line during overflow conditions?
Spillways are typically designed to be wide enough to handle calculated flows. Water begins to flow over the spillway gradually as the water level increases. Spillways are grassed/vegetated or rock lined for erosion control and soil stability.
Betonite seals are often poor seals near the upper water line or above the water line where the water level fluxuates and the soils are allowed to periodically dry out, crack, and then leaks result. That is why it is best to have a very thick clay liner or wide, tight core trench as a seal for the upper 5 to 6 ft of embankment around the pond. If I had to use a beonite seal in the upper 5 ft of embankment, I would make sure to work the betonite at least several feet back from the water line into the soil in layers with compaction of each layer. You don't want this to leak which is where it is most likely to leak. It will be much cheaper to do it right the first time rather than try to "fix a leak".
You should also realize the possibility that your soils maynot be appropriate for building a pond.
Spillways are simply a water management tool. Some ponds have pipes as the primary spillway. All ponds should have an earthen emergency spillway. Some ponds have only an earthen spillway, depending on watershed size. A pipe gives better control where you want the water to go, especially if you want to use the water elsewhere. Plus, you can turn a pipe on, or off, with a valve. An earthen spillway only spills.
Structural integrity won't be compromised if the dam is properly built. Bentonite is used to seal porous soils. Porous soils are not necessarily bad construction soils. They just don't hold water.
If I were you, I would learn as much about my dirt as possible. Find out what's in it, how compactible it is, and how much clay content there is.
Then, decide what to do.
Be the dirt...beeeeeee the dirt!!!
Beeeeee the dirt? Between getting flack over moving some trees and "beee the dirt", I think we have some real comedians on this site! So, here's a question that NONE of the books seem to answer - If I am to "be the dirt" and am a core trench, what is the best dirt combination for me to be?
i would start out with: what kind of dirt do you have to start with? have you sent a soil sample yet. when you squeeze it up in your fist does it form a baseball and stick together and hold its shape, or fall apart (when damp)? secondly, if you have bad soil, do you have a supply of clay on your property close by? how do you know? well, a backhoe operator can dig you some decent size holes/deep...sometimes the clay can be 6 feet or more below your topsoil. but also think to yourself, self, do i have any soil to begin with, or is it a bunch of shelf rock under those cedars? also, if you have some down trees around other parts of your property, check the dirt under the bottoms of the stumps, any clay there? if not...may check your local dirt company...approximate costs here in the south, not sure about CO are... "gumbo" grade...good adequate stuff for 42 dollars a dump truck load (standard dual axle dump truck) or "road quality clay"... that deep red looking stuff that sometimes cracks during drought...more expensive..about 70-80 dollars a load.
I hope this helps, i hope you have as much fun with your project as some of us have, sounds like it will be a nice place.
What did you decide to do about moving those big trees? if you are interested in purchasing trees, i have found good prices by joing the National Arbor Foundation (10 bucks a year, 15 free trees or so a year with membership, and lots to choose from).
one more thing. you mentioned that none of the books touched this subject. but i thought i saw a section similar to this on the "Basic Pond Management" book offered on this site. i can't remember for sure, but if you don't have that book you might check there.
mark
Mark, You are right that "Basic Pond Management" does have some information about the core trench with a nice cross section detail. The problem is that it just calls out for "core fill". Both of Tim Matson's books do something similar, but without a clay mix "recipe" (all of us women like to see the exact mixture required!). So, your thoughts are very useful. I have had a soils test done and it is not pretty - sand to about 10' and then clay/sand mix to about 12, clay down around 15. Certainly deeper than I had hoped. So, we are still in the figure-it-out stage.
Now the trees: Did NOT move the willows after hearing so much negative advice from the experts on this site. However, we are still planning to move the fir trees from our neighbors on the mountain. Around here there is a great deal of bartering, she wanted some of my jumping saddles, I wanted a few of her thousand+ trees. A tree mover will handle the job, so the actual cost is mostly in the digging part ---- a lot like my pond project! We decided to get the pond in first and then place the trees further back. Hopefully we can still block the view of the new alpacka farm next door! Somebody forgot to tell my neighbors that this is cattle country!
Bill and Bob:
Great info.....if bentonite seal in a pond wasn't a concern - how close to the waters edge could you plant evergreens/white birch etc for their reflective value and color in the water. Any other suggestions of trees, shrubs and plants that could be used in by rehab. project of some 6000' of linear shoreline for my gravel pit in Southwestern Ontario. Thanks
Rowly
This site's always great for a chuckle.
Beeee the dirt?
I love that.
Most books won't be specific about dirt because dirt is never specific.
In an ideal world, on an ideal mountainside, if you can combine soils to create dirt with 30% clay content, you have soil that can be compacted. Compacted soils leak less, are better to build with, my dear, and won't eat your dam.
Without having to consider bentonite, plant trees as close to the water's edge as you dare. Different trees have different needs. Willows need wet, oaks need dry. Base proximity of planting on the needs of the tree.
Beeeeee the treeeee.
Ranch Girl, you may not have a hopeless situation with the clay down at 15 feet. here's what came to my mind... how big of a place do you have to build a pond? here's why. if you plan to build a biiiiigggg dam, then you will need a lot of back fill on the back slope of the dam. now, if you are building a biiiigggg dam, i.e. in a ravine or whatever, you may require a lot of back fill. so your dozers would scrape the top 15 feet or so off (which i admit, is a lot, probably too much), and place that top dirt layer where the back slope area of the dam is to be. then, the clay would be exposed and the experience dozer guy (or girl) would then use that for the trench and front slope, bottoms and sides of the pond/lake. if you plan to build a small pond, your best bet may be a liner, or hauling in clay/bentonite. hope this helps.
one more thing...you may want to build your pond first, get an engineer or surveyor to come out and "shoot your lines/slopes/water levels" so you know where the water levels will be etc. now, before i invest much time/effort/money into those big trees/moving them...i personally would make sure your pond holds water and fills. then do the add-ons/ touch ups later. mark
I feel like a kindergarden kid! One minute I am beeeeing the dirt (that would be an interesting costume) and the next minute I am beeeeeing the treeeeeeee!
Thanks for the dirt recipe Bob!
oops, forgot you Mark! Yes, will do the pond first and THEN see how things go with the water before moving any trees. Good thought.
As to the size, I have plenty of land and could do something as large as 20 acres in the valley area - but I think the pump on my well would probably burn up every few days just trying to fill it. Therefore, I am trying for about 3/4 acre. Also still debating the dig out vs embankment approach. Next thing I know Bob Lusk will tell me to "beeeee the dammmmmmmm"!
After it is all done you will have to "be the water" to make things successful.
If you think about it, the best ranch foremen are range specialists or, as one told me, grass farmers and soil students.
All of the fertilizers, feed, aeration devices, beneficial bacteria, stocking rates, etc. aren't as important as the actual quality of the water.
Sooner or later Mama Nature catches up with artificially stimulated environments and gets even.
Just my thoughts and I am a fertilizer salesmans poorest customer.
Very good point dave d. Ranch girl...that may be something you need to consider...if you have a lot of manure/fertilizer going into that small of a pond...you could have your hands busy. i saw that on your profile you are an architect. i'm sure in your business you must plan ahead. i really think that you ought to step back for a little bit...get some professional advice to come out to your place and give their professional opinion, ideas, etc. you may get a 3/4 acre pond..but with horses/cattle etc nearby, you may wind up with a sludge pond. how much watershed do you have, and what makes you think you need a well? i don't mean to put a damper on your expedition here, but i think you may sink some money into something that needs a little more planning pro eval. (by the way, i am not a pond expert, just a pondmeister wanna be like many others here!) but, you may want to go ahead and contact your soil conservation dept. and get on the list for the guy to come out with his lasers/levelers etc to shoot your lines/spillway etc. a 3/4 acre pond probably won't be too expensive. buuuttttt, you said you possibly could do a 20 acre lake!! now that my friend would be niiiccceeee! there are two ways to look at it...experiment and see if the 3/4 acre holds water, learn with or . or, plan ahead, get some pro advice, and see if you can put the money from the 3/4 acre pond towards a bigger pond. with your architect background, you could probably have some great ideas and expertise/design ideas about the pond. but i would use your expertise in conjunction with a pond building professional. just a suggestion to try to keep you from sinking money into a hole. hope you see that i'm not trying to discourage you from exploring pond building...but it gets expensive quickly, and i just don't want to see you waste money....because you could be putting that money into a bigger better pond that will last. as said many times on this web site...pay now or pay later...and that's pretty true.
by the way, did you ever squeeze that dirt between your hands?!!! mark
ranch girl, one more thing.... you said you felt like a kindergarden kid...great...we should feel like that everyonce in a while life was good then...still is!! ponds are fun, a big adults playground...except when you were in kindergarden, it was mudpies and puddles...now its "beeeeee the dirt" and dams and ponds/lakes.
keep having fun, and keep us posted along the way of your pond experience.... mark
Mark, thanks for your comments about stepping back and planning better! You are right, but there are so many questions that need answers it is hard to plan without good advice from those "in the know". While we can design great hotels and restaurants, being in the design business is good only to the point of knowing ones own limitations -- with this pond project I have certainly met mine! BUT, I also like to think I could gain enough knowledge to understand the issues around a project to know that I am asking the right questions and am finding the right resources. This website has given me a tremendous amount of insight and I have certainly enjoyed the many comments from you and others.
So, here's the update... we had the soils test done with clay showing up at 10 feet. We have also determined that this needs to be a "dug out" pond of about 1/2-3/4 acre because of the "wetlands" designation on the lower level of our property where the creek is. The pond location will not be accessible to any of the horses or cattle, so we need not worry about waste getting in it. I have also looked at a couple of options (at Bob Lusk's suggestion) for first a liner and second a betonite mix. The liner is a pretty expensive option using EPDM, so am wondering about the alternative PVC product. Certainly there are a number of posts about that issue here to read, but have yet to find a definitve answer to their differences or a PVC liner company to give an alternate quote and specification. As to the betonite, we have one of the largest brick making companies in the US within 10 miles from here and they sell clay in bulk, so we are checking with them about the actual composition of their product and the application in this use. One of our neighbors dug a 3/4 acre pond with a 12" clay layer and then a 12" topsoil blanket a few years ago with good success - so there may be an option here. But as you say, pay now or pay later. Once we get an excavation cost at the deeper level with the betonite, we can compare that to a more shallow pond using a liner.
Lastly, and on a personal note - I need to know how one becomes a "Lunker" with absolutely no knowledge to offer?!! I was taken back a bit when my designation changed last week from a "Fingerling" and I'm not sure how to feel about this - most especially when the Bill Cody's of the Pond World are also "Lunkers"! Now, besides this question, how should a GIRL feel about being a "Lunker"? Just think about the potential psychological impact of such a term! This is not exactly what my father would have preferred I aspire to... but maybe not! A few thoughts on alternate designations: some posts on this site could be from "Blow Fish" (you know the type); some from "Guppies" (which really should be the term for us pond owner "wanna be" type); some "Perch" from those that want to "read only"; But my real question is this: Where are the "Angel Fish" (other women with questions) or... the "Salmon", like me, who seem to be swimming upstream with their project!
Just some "fish food" for thought...
Well, Lunker sounds better than whopper.
I felt the same wauy when I saw all those stars under my name. I have as many stars as Bill Cody!There are some guys who manage ponds for a living that only have four stars. I'm just a weirdo who likes to learn about fish.
It seems now all folks have lunker under their name including new folks. BrianH if you click on the rankings it not only has stars but how many times you have been ranked. If my memory is right I voted 5 stars for you awhile back after some kick butt post you had. ALot of you folks may think your not Pond Pros, but you help me from time to time. Thanks!
I was a bit surprised by a response to my comments on the ratings by Dudley of Louisianna, and having thought about that posting for a bit, am now as surprised to see it gone. I had not realized there was a mechanism for removing posts - but in any case, in no way did my light-hearted comments about the member designations mean to be disrespectful of what the PB team has established or, to any other member. If I was, I apologize.
ranch girl, first of all, don't feel bad if someone took your comments wrong...most people on this site have good sense of humors...others...well, they would probably get pissed off if you spelled bentonite or betonite. key point...you can't please everybody. have fun, avoid foul language, don't be afraid to respectfully poke fun at certain things and joke a bit. there's people everywhere that are so anal retentive you could stick some charcoal up their butt and they'd poop a diamond!! (i think that means they are so anal retentive/tight a..es that they would compress charcoal into a diamond...just one of those old sayings i guess. have fun, i liked your lunker/perch/guppie comments. i believe you are a lunker after you post around ten sites or so. you are moving up girl, mooovvving up....we are all so proud to see our little girl grow up into a lunker!!!
yes, take a little time and plan ahead, just like you would an architect job. be patient.
these folks are great. keep looking back on the previous post topics, and purchase the books offered on this site, and you will keep learning a bunch. i think most of the guys are glad to see a woman posting on this site because ...would be great to have our wives that interested in pond management....can you call my wife!!!??? ha, kidding. take care, keep us posted. mark
Thought I had removed my post before anyone got to it, Ranchgirl. It seemed funny when I wrote it, as it was intended to be. But then I decided that you might misinterpret and so removed it. Seems as though I was correct in that regard. Your posts are clever and enjoyable and are to be encouraged. Certainly, I intended no offense and hope you'll accept this apology.
OK, on this site you go from fingerling to Lunker for posting ten times. As far as the stars go, I felt the same as BrianH, I got 5 stars for making a suggestion about the website that they used(I believe). Personally, I think a bunch of us should rank Greg Grimes(I allready did) and push his rank to 5. That's the one star ranking that bothered me. There's a man that does some serious posting, and puts out alot of information for all of us! Thank for taking the time Greg.
Jimmy
I too tried to push Greg to 5, no luck...we need more votes ! As for women aboard...yes and no. Ranch is trying to improve and is doing research, I think my wife would try to find the prettiest fish and color coordinate them !
Eastland, be afraid...be very afraid! If someone posts a little joke, DON'T JOKE BACK! There is no way to know who the charcoal stuffers/diamond producers are until it's too late.
Hey Bob, how about waving that newly aquired weighted magic wand of yours.Last I saw Greg was 1 post away from 500, that alone deserves 5 stars!
Heck: I've tried to get Greg to 5 stars several times. There is no way he and I should both be 4 stars. However, if he move to Texiz?????????????
Hey Dudley, et. al., - Thanks for the your note about the earlier posting. I understand completely and have often wanted to "pull back" an email, or even something said verbally, that didn't come out quite like I intended it to be. And I'm sorry not to have responded, but have been running hard with a few crisis issues at the office. So to all... don't "be afraid...", we are all big kids here and a joke is only that... a joke. Besides, every client I have in Louisianna is BEYOND polite and gracious, so I first wanted to believe that it was "I" who had offended, and thus my earlier note.
Lastly, I'm not here to disrupt anything, only to learn from those Pond gurus I have so quickly gained great respect for. Maybe a little levity was all I had to offer back for now, but someday soon that will not be the case!
Best to all from a very cold Colorado! PS - starting a new post question, so please pipe in if any of , you can help me...
I'll talk with our webmaster, and see how the ratings happen, and who does it. I bet he'll give me a "magic wand."
Hey guys I'm blushing over here. No big deal what so ever about a 4. Heck I think 4 is good. I appreciate the thought though. I think if someone puts me down for a 1 it will take alot to push it up to 5. I say what I feel and have ticked soembody off I'm sure. The rankings mean nothing to me, but the fact you appreciate my efforts to educate is plenty enough.
THANKS!
I still remember the day i too became a "Lunker". There I was, sitting in my make shift computer station, laptop in front of me with my posture looking like Schroeder from the ol' Peanuts/Charlie Brown Cartoon strip (Schroeder was that piano playing character always leaning over his piano...just picture it).
The room was dim, the smell of coffee at my side. Wife and son (a 7 pound adorable little yorkie dog) asleep in bedroom. Pager was quiet, all was good.
Then, i clicked..."Add Reply".. then, and there, my life changed! My shoulders back, chin up, Schroeder posture gone, a glow on my face, a smile... I said to myself, "self, could this be?"
I looked up...thought i saw a glowing figure of Bob Lusk floating overhead with his magic wand and booming voice...about to tap me on my shoulder, honoring me with that status of..."Lunker". Did I make some profound posts that changed someone's life or pond? Did i rescue a pond from the edge of destruction? Did Greg Grimes just raise a 20 pound Largemouth in one of his ponds due to a piece of advice that little ol' pondmeister me offered in one my posts??? How was I going to thank "the little people" that made this possible?
My wife had awakened from the booming noise and bright lights. she shook me, "Mark [shake, shake], Mark [shake,shake], wake up, turn the computer off, there's a thunderstorm going on"...and then, and only then, had I realized...i just posted my 10th post...and THAT, my friend, made me a Lunker! Ahhh, what a day. mark
Mark,
That's Funny! :p
Ric
well, i'm glad you did ric, because someone didn't...after i posted that..i got 2 more "votes" and i went from 5 stars to 4, in a matter of seconds!!! man...at least now i can truly sympathize with Greg Grimes...i guess he and i are both "Not Worthy" !!!! someday, i will be a 5 star'r again...someday, soommeeeday!
thanks for a good laugh to get the day started!
Mark,
I would try to boost you back but I've already rated you & it seems you can only rate someone once. Look on the bright side .. they gave you the oportunity to relive getting to 5 again!
Ric
thanks ric for the encouragement...but i tell ya...i am NOT going to sleep with Bob Lusk, just so i can get 5 stars again. i'll just work harder, and maybe someday, sommmeeeddaayyy!!!!
ranch girl, what did you decide to do about the trees after the pond fills up and you determine the exact water level? i was just curious on the root systems of the evergreens next to the water because i'm debating on planting some near mine? i guess willows are out for me, to many negative comments...have you come up with any ideas (for evergreens)? mark
Mark,
Your posts can be hysterical! I think Bob L should come up with two ratings - one for technical knowledge and one for just plain encouragement of site comradery. I would give you high ratings in both! There are so many days I feel overwhelmed by what should be a much simpler question - so, the responses I get here are always helpful and yours are ALSO very encouraging - thank you! But, if Bob could wave that magic wand in my direction, I would ask for only one thing... better soils!
Back to trees... yes, I have decided to hold off until the March/April transplant season when the trees are just starting to come out of dormancy. Hopefully the pond will be in by then and we will be better able to determine the exact location for the evergreens. According to the Arbor Foundation, the roots can go 25-40 feet. Therefore, we will plant further out than that. I am still so thankful to this site for warning me off moving the willow trees - saved several thousand dollars in moving costs and what sounded like MANY headaches in the future.
As to the depth - still waiting to hear back from the excavator about going deeper than 10' to take clay and move it onto the sides (another Bob L suggestion). My budget is already tight, so will just have to keep my fingers crossed!
ranch girl, did you ever look at going ahead if costs allow and doing the 20 acre lake vs. the smaller pond?
i think i'm going to do some evergreens and a few maples/bradford pears etc...try to avoid too much leaf debris. and i'll definately avoid willows!!
mark
oh, thanks for the compliments, this site and it's topics are fun, i am glad we can all have a good time and enjoy each others comments, and at the same time learn.
ranch girl...thought about something. you said your clay is 10 feet down. have you thought about selling the dirt on top of it (assuming you don't need it for backfill behind your dam) ??
this may offset some of your costs
mark
Question...... has anyone had any luck with trying to eradicate some willows growing naturally along the waters shoreline by cutting these willows to the ground and installing landscape fabric over top of them and covered with a layer of rip rap rock. I'm in the process along my east shoreline and 2 islands (some 1200' or more in total) in doing this. I have already completed some 400' plus with no growth up thru the landscape fabric and rip rap rock but I guess next spring and the vigorous growth of these shrubs will truely tell the story of sucess or ........ Thanks
Rowly
Rowly, I believe in a foliar pesticide. It always works. You have to be careful with overspray.
Rowly, cutting willows low and painting the cut surface of the stump with undiluted glyphosate (Roundup, Rodeo, etc.) is very effective if the application is made within an hour of making the cut. I always apply within minutes. As a spray for small willows or dense stands of small willows I use 3 fluid ounces of glyphosate and 1.5 fl. oz. of 2,4-D per gallon of water, with a surfactant. Either herbicide alone would probably work well but I find the combination especially effective. Of course, you know not to waste herbicide on dormant trees. Hope this helps you.
Another helpful tip for the glyphosate application is to add a tracer dye to the mix so you know which ones have been painted.
Robert B
Thanks for a truly ingenious suggestion, Robert. A friend of mine once said, "If you can't use your head, you might as well have two patooties". Obviously, you don't have that problem.
Dave/Dudley and Robert:
Thanks for the info. I used landscape fabric and riprap rock along my east shoreline mostly for beautifulcation purposes and erosion control. Hopefully the landscape fabric and rip rap rock will stop the willow from breaking thru the fabric....if not I will use your suggestions.
Rowly
Dudley, would your formula work on tallow trees, had any experience with them. Jim
Jim, if by "tallow" trees you are talking about those nasty trees that produce those little pods, each pod containing from two to four seeds, with each tree, regardless of size, producing twelve+ billion pods with 300% germination, the stump painting will work if the tree is cut low to the ground. The spray combination I mentioned will also work, but there is probably an herbicide that would work better. Kelly Duffie, and perhaps others who post on this site, would be infinitely better qualified to advise you. Incidentally, I've heard those trees referred to as coffee trees and chicken trees but their botanical identity remains a mystery to me.