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ingrid_vc

Pepper Tree Leaves as Mulch - Yes or No?

I'm revisiting this topic since the results of a previous question about this were inconclusive, and we are having people come in to chop down dead trees, cut down weeds and remove the leaves from under the pepper trees in order to be prepared for any fires. There are thick layers of leaves under every tree and rather than having them carted off I'd like to use them as much-needed mulch in the garden. There is a belief that the leaves are toxic and will hurt plants that are mulched with them. I'd love to have your opinion. I'll probably also post this question on the regular rose forum.

Thanks in advance for any information. This job will be done tomorrow so I'd love to hear from you as soon as possible.

Ingrid

Comments (24)

  • jerijen
    9 years ago

    No. I think they retard the growth of other plants.

  • porkpal zone 9 Tx
    9 years ago

    Are there weeds growing under your pepper trees? If so the leaves can't be very toxic. If not then jerijen is probably right.

  • lazy_gardens
    9 years ago

    The only studies of allelopathy in Schinus molle are the extracted essential oils from the seeds, on wheat. So don't mulch you wheat field, OK?

    Personally, I'd have the whole tree chipped, keep the chips and use it as mulch as well as the duff underneath it.

    The "thick" is what's probably the weed suppressing factior, as is the dense shade they cast.

  • Adam Harbeck
    9 years ago

    You could pile it and let it break down before use. But that's probably overkill. You will get seedlings popping up though.

  • jerijen
    9 years ago

    We have two pepper trees -- what we call "California Pepper Trees," tho they originated in Peru). There are no weeds growing under them, though we have had at least one volunteer seedling.

  • jerijen
    9 years ago

    If you have a female tree, part of the mulch is the red "peppercorns." Quite by accident, we have one of each.

  • ingrid_vc so. CA zone 9
    Original Author
    9 years ago

    Thank you very much, everyone; I'm going to take that as a resounding "No". Catspa's comments were especially helpful in convincing me since this is not a desirable mulch in any way.

    Ingrid

  • nikthegreek
    9 years ago

    The reason weeds do not thrive under Schinus molle should mainly be its very efficient, superficial and spreading root system. I have noticed no obvious allelopathic symptoms. We call it 'false pepper tree' over here, btw. I have a large one in my garden, it has never set fruit so I suppose it is a male although I can't be sure since there are no others in the vicinity. Are females strictly female or they exhibit a small degree of self polinating capability? Lots of bees frequent the tree during bloom time, there is a constant buzz around it. I'm not sure this says something with regards to its sex.
    Nik

  • roseseek
    9 years ago

    NO! Not even prickly cucumber grows under either the Brazilian or California peppers here on this hill. Where there isn't pepper "mulch", there are tumble weeds, thistles, mustard and all sorts of "weeds". There are NONE where there is pepper litter, either where the areas receive at least half day sun or in the parts which seldom receive any direct sun. Does that tell you anything? Kim

  • Sow_what? Southern California Inland
    9 years ago

    I'm concerned as well, since we're using California Pepper as mulch at Humpty Dumpty House. I find it effective as mulch, and not terribly unattractive, but am wondering if our plants are now in danger? I looked for information in the UC system, but didn't come up with much of anything useful.

    Can you keep the leaves for compost, Ingrid?

    jannike

  • hoovb zone 9 sunset 23
    9 years ago

    My beef with that stuff is the seedlings that result, which I am frequently pulling. Likely the reason for no growth under them is that S. mollis has greedy surface roots that suck out all moisture from the soil.

    Do you have a place you can pile it up and compost it? That would eliminate any possible "bad" chemicals. Pile it up, water it, and then put a tarp over it for 6 months.

  • catspa_NoCA_Z9_Sunset14
    9 years ago

    Nik, my male tree attracts hordes of bees, too, and then the fall and spring migration of warblers, going after the bees. The volume of the buzzing when the tree is in bloom is amazing -- thousands of bees.

    Bindweed, ripgut and other grasses, rosemary, and sow thistle do seed and grow under my tree, in greater density where the canopy lets some sun through. If the litter stayed intact, the weed seeds would have a hard time making contact with solid ground and germinating but it never seems to stay intact here -- always plenty of breaks in the mulch for weeds to get started. It is also very dry under the tree -- weeds dry up fast there when there's no irrigation.

    The tree sits atop a short slope at the back of the yard, facing south, so a fair amount of sunlight filters through under the part that is in my yard. Benches or level areas on the slope under the tree where debris has settled and broken down over the years, forming a layer of fluffy duff, have proven to be ideal places (except for the constant, annoying rain of debris) to plant slightly tender succulents and other exotics needing well-drained conditions. The canopy in conjunction with slightly higher ground makes for a significantly warmer microclimate in the winter, so that Echeverias, Bulbine frutescens, Cotyledons, scented Pelargoniums (Clorinda and the very tender Pelargonium citronellum), and others that get "nailed" in other parts of the garden during a cold snap come through just fine under the pepper tree, plus the filtered sunlight prevents sunburn during the heat of summer.

  • ingrid_vc so. CA zone 9
    Original Author
    9 years ago

    My problem at least has been satisfactorily resolved since the tree/weed people will give me mulch from ground-up tree trunks and branches from previous projects which they'll pile in a mound on my large concrete pad. I also have leaf litter from the avocado tree that's being cut down because it's nothing but a skeleton; what a water guzzler and never a single avocado. Needless to say it got mostly rain water since I'm not about to waste water on a tree that has no place in the new drought-stricken time we now live in.

    Ingrid

  • Sow_what? Southern California Inland
    9 years ago

    Ingrid, do you know what kinds of trees that mulch is from, and that it won't cause any problems?

    jannike

  • Kippy
    9 years ago

    Jannike

    From what Tom Spellman of Dave Wilson Nurseries said, it is a good thing to have the mulch/chips from a variety of trees rather than a single source (type of tree). He said he has no worries using most any kind of tree trimmer chips that way because there is never too much of any one type of tree.

  • ingrid_vc so. CA zone 9
    Original Author
    9 years ago

    jannike, that is in fact a very good question, but these are reputable people we've used before, who I'm sure want to be hired again, and they have a good knowledge of what constitutes desirable mulch.

    I'm glad we're doing this now because Cal Fire is going around all the rural areas and will be fining anyone who doesn't have brush and weeds cleared and trees limbed up. This was not a cheap project but is a lot better than losing our home in a wildfire. We have everything in place to fight a fire rather than evacuating, and getting rid of fire hazards on our property is very good for our peace of mind. Now that the wildfire season is year-round it's not a question of if it will happen but when.

    Ingrid

  • Sow_what? Southern California Inland
    9 years ago

    Thanks hoovb, Ingrid, and Kippy. Kippy, I've spoken to Tom, and he recommends chips from at least three different types of trees. Problem is, when it comes from tree trimmers, you're getting it off the truck without knowing exactly what you're getting and its history. I was wondering about weed seeds, pesticides, etc, but really wanted to trade out a lot of our mediterranean gravel mulch for wood and leaf mulch in order to nourish the soil. Now I'm concerned that our plantings might be harmed, at least from the Schinus molle component, and that I might be pulling pepper tree seedlings for the rest of my life.

    Ingrid, I hope your fire safety project went well.

    jannike

  • nikthegreek
    9 years ago

    Just a general comment, not applicable to roses. Many a mediterranean climate drought tolerant native plant will suffer when too much organic material exists on or in the soil. Native plants have evolved to thrive in conditions where organic content is less than 2-3% in the soil and will not tolerate overly fertile soils. They might exhibit unnatural vegetative growth, unsustainable during dry and hot periods and may become victims to soil borne fungal and bacterial attacks. Just something I thought people gardening with native and draught tolerant plants, which most roses are not, in such a climate, should keep in mind.
    Nik

  • hoovb zone 9 sunset 23
    9 years ago

    they'll pile in a mound on my large concrete pad

    just to note if you want to compost that material it is better off on soil, because the microbes that do the composting live in the soil and migrate their way up into the material. On concrete not much happens.

  • ingrid_vc so. CA zone 9
    Original Author
    9 years ago

    hoov, I wasn't thinking of composting it but just putting it on top of well-watered soil in the garden before it gets much warmer. We'll be in the 80's and higher by tomorrow and I want to have it all in place as soon as possible.

    Thank you, jannike, they did such a good job that the place looks bald and twice as large which probably also means twice as hot. It's amazing what a difference it makes to take out a few trees and trim the rest. Personally I like more of a lush look, but safety has to come first.

    Ingrid

  • odinthor
    9 years ago

    Different plants show different sensitivities. Under my 60-year-old Brazilian Pepper, in the 4-6 inch thick mulch of its fallen leaves, I have several kinds of Aeoniums and Echeverias growing happily, and used to have an equally happy growth of Swedish Ivy (Plectranthus verticillatus). The shade cast seems to be much more of a problem than the pepper tree leaf mulch. Close by, I have a flower bed thoroughly infused with leaves from the pepper tree which has hosted Primroses, Doronicums, Gladiolus byzantinus (so much so that it became a weed and it took me three or four years to eradicate it), Digitalis, Diplacus aurantiacus, Pelargonium tongaense, Thalictrum, Lilium, Impatiens, Poliomintha longiflora, Narcissus, etc. etc. etc. It may be that the Brazilian Pepper is less noxious than the California Pepper; but there's my experience, for what it's worth.

  • Kippy
    9 years ago

    Jannike, the question of weeds and pesticides came up when Tom spoke here, he did not have any concerns about either for the tree trimmers chips. Most of the time people are not spraying large trees do to the size of the tree and there are few weeds in the trees as well.

    I have been more concerned about the grind recycled mulch the county offers free. Because that is weeds and pesticide central But it has also been ground, mixed and has had some time to cook as well. He actually liked that source better

    In your situation, the gravel may be better in some places and the chips in other. Gravel is probably easier to walk on, but hard to roll on if clients are in wheelchairs. And gravel under the plants unless you do a lot of blower work will be gravel in the soil before you know it. Especially if that Jacaranda gets going. FYI I am not overly thrilled with the quality of compost with a high level of Jacaranda in it, it seem to be more hydrophobic than one would expect (the leaves and twigs) The flowers seem to break up fine.

    Remember when you get tree trimmings you are getting usually the whole tree, green and brown. The green will break down much faster.

  • Sow_what? Southern California Inland
    9 years ago

    Kippy:

    I only started mulching with woody/leafy materials from outside our property before last winter, and have a reserved opinion so far. Before going to outside sources, I was a stingy mulcher, since I didn't want to steal too much from our unfinished compost. Some of the mulch is breaking down nicely, but I worry about it mixing into the soil prematurely, especially in beds that are being heavily planted. It does seem to be contributing to water conservation.

    I share your opinion about the free county mulch and compost. I've used it many times by the scoopload, and have always gotten a bad result. I finally redid all the beds where it was used, and the plants are all thanking me. We compost in earnest here, but can't meet our own needs, so I supplement with purchased compost. The only things that go into our green bin are spent tomato plants, rose clippings, weeds, and diseased plant materials, and that's what's going into the county's mulch and compost. Most people around here contribute even worse, since spraying is common.

    Thanks for your comments about wheelchair accessible paths; that's a subject close to my heart. Our paths are mostly decomposed granite: cheap to buy, easy to build, natural in appearance, and good for feet and wheels. I encourage people not to walk in the planting beds.

    I'm struggling with the issue of granite mulch. I love the look for a dry mediterranean garden, especially with lavender. But in the past I used weed cloth to keep it from mixing in with the soil. Weed cloth is fine under pathways, but I'm not so sure it's a good idea in planting beds. Any suggestions how to use gravel are welcomed.