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Question from Desiree:
Recently I bought three weeping willows–the After Dark Jervis Peppermint Willow tree, peppermint willow (Agonis Flexuosa), and Australian Willow (Geijera Parvifolia). These trees were purchased through a city plant a tree program. Not much inquiry was done, however I was told that these particular willows are non-invasive. I planted the smaller of the three–the After Dark Jervis in a garden area next to a pool. The other two are planted about two feet from a bull nose brick wall on a split level yard. It’s only been about three weeks since planting. Now I’m wondering if planting these Willows by the pool, and the bullnose brick will tear up the pool and brick. I understand these willows grow fast too. Give me your advice, because I don’t want to risk tearing up the pool or brick walls, and if I should move it, I’d want to do it soon. Thanks.

Answer from Pat:
Australian willow (Geijera parvifolia) is fast growing but known for being a basically trouble-free, drought-resistant tree with deep, non-invasive roots good near patios, streets, or to be planted in groves and okay in 5X5 cutouts. It is best in well-drained soils. Any tree planted in hard soil will tend to have more surface roots than if planted in deep friable, well-drained soil the roots can easily penetrate. But this tree eventually will grow to be 25 to 30 feet tall and of course the trunk will get fat in that amount of time. It probably will be fine for many years since if the soil drains well the roots will go down and not on the surface. It would have been wiser to plant the tree 3 feet from the wall in consideration of the eventual thickness of the trunk. Nonetheless, you planted it two feet from the wall. What’s done is done. In this case I would leave it. It should be okay for many many years. Next time remember at least three feet away from walls is a better distance.

When I was an undergraduate at Scripps College in Claremont Calfornia there was a tall and lovely, smooth-barked lemon eucalyptus (Eucalyptus citriodora) that had been planted 25 years earlier with the trunk between two and three feet away from a tile-topped white stucco wall. I loved that tree and used to stand on the wall next to it and hug it when I was in college. I would visit it every time I went back to the college. It is now 60 years since I was in college. When I went to my sixtieth reunion my beloved tree was gone. It was recently cut down. I had noticed the trunk beginning to push against the wall. That gives you an idea of the time span. Think of the eventual size of the trunk. Look at old specimens of the same tree to see how thick the trunk will grow. In this case, since E. citriodora is deep rotted Please change to: rooted, it was the trunk that hit the wall not the roots that caused the problem.

In respect to the After Dark peppermint willow (Agonis flexuosa ‘Jervis Bay After Dark’) this is a slower-growing tree than the regular agonis and so far seems to grow to a smaller size. It should be fine near the pool. You don’t mention how close but I would trust at least two feet away from paving? If closer than two feet I would move it. Since it’s slower to take off this one would be easier to move. Consider eventual size and the shade on the pool. Will the foliage shade the pool or did you plant it to the north as is the best practice? Though this is a non-drippy tree you don’t want tree branches overhanging a pool.

Finally the peppermint willow (Agonis flexuosa). This has proved to be one of the best small trees for California gardens, easy to grow and trouble-free. It is not known for having troublesome invasive roots. It is also used as a street tree in 5×5 cutouts and it is also tolerant of many kinds of soils and much or little watering. I think it will be okay for many years.

The problem with moving these trees now is that it could set them back a bit. Thus I would leave them where they are. Three feet would have been better clearance but in the case of these basically trouble-free trees I think two feet will be okay for many years. If you tend to be a worry wart and will lie awake at night worrying about this matter, move them immediately but be sure to dig up as much of the root ball as you can and apply humic acid mixed according to package directions and drench the roots and soil after planting to avoid transplant shock and encourage rooting. If you cannot find humic acid at a local nursery specializing in organic supplies, you can purchase humic acid in powdered or liquid form from Peaceful Valley Farm and Garden Supply. If you decide to do this move the trees immediately then send for the humic acid and use it as soon as it arrives.

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8 Responses to “How Far to Plant Peppermint willow (Agonis) and Australian willow (Geijera parvifolia) from walls and paving”

  1. marjie grand May 13, 2012

    We redid our back yard and I. Planted peppermint willow in center of a small patch of grass surrounded by flagstone pavers. It died in a year. Tried again….same thing. Its fine for about 6 to 8 months and then it suffers a very fast death. Third time was not the charm either. I changed the soil going down 4 feet put drainage rocks at bottom. Put a watering tube so water gets to roots…..nothing wrked and the third tree died as well. They were all about 5-6 ft when planted. Its been two years since the last one died. Would like to try again. Help please?

    Reply
    • Planting a young tree, or sapling, out of a can into an extablished lawn or planting it bare-root into a lawn puts the newly planted tree at a huge disadvantage. Trees planted into existing lawns often grow very slowly. Sometimes they die. Here is why: Lawns are heavy feeders. Depending on variety, once they are established their roots extend a foot or two or even more into the ground and they grab every bit of nitrogen and moisture they can obtain. If you add fertilizer on top of the ground to feed the lawn and the tree at the same time, the grass will rob every bit of that nitrogen before it gets down to the tree roots and the tree will get none. Tree roots also live in the top 2 or 3 feet of soil so they will be fighting for their life against the lawn roots which are far stronger and more aggressive. Tree roots do not head straight down to China as is commonly supposed. Instead they attempt to move out sideways and in this case they will encounter a mat of vigorous grass roots or at best they will encounter dry, depleted soil beneath the grass. Secondly, planting into a patch of grass surrounded by pavement is another problem. No water can penetrate through paving to water the tree roots (if the roots of the tree ever managed to extend that far.) All too often people do not water a patch of grass surrounded by pavement enough to allow water to penetrate deeply. No fertilizer is available under pavement either. Additionally our native soils here in Southern California contain mighty little if any nitrogen. We need to add it. So even if you tried to feed the tree—something that is noticeably absent from your query—or even if you perhaps fed the lawn hoping the tree might grab some (which of course it was not able to do), it certainly could not obtain any by the time its roots reached the pavement. Thirdly, creating a sump by putting gravel in the bottom of a planting hole does not cure bad drainage. A layer of gravel in the bottom of a planting hole simply creates an under-ground swimming pool for roots. As soon as you water the plant, the gravel will fill up with water and then sit there indefinitely. The tree roots will eventually reach the water and promptly rot. This may explain the sudden death of your second tree, even if it does not explain the death of the first. The fact that you tried to do something about drainage (even though you chose a method that we now know does not work) makes me think drainage might be insufficient. Building a sump has long been discredited as a way to fix bad drainage. I should also warn you that many properties in California have “a spot where nothing will grow”. This was usually caused by workmen washing out wheelbarrows and tools used for concrete and plaster or washing paint brushes and paint cans onto the soil in that area during the building process. I hope this is not true of this spot on your property. The fact that a path goes round it makes me wonder if the soil is too alkaline. You might have it tested. If you do all the things below and the tree does not grow I fear you have one of those spots where nothing will grow. If this is one of those spots, there’s not much you can do other that to replace all the soil with good top soil to a depth of at least three feet, but if as I hope this is not the case, here are my suggestions for make your third attempt successful: Dig out all the grass and replace it (after planting the tree) with organic mulch or ornamental river rock. Alternatively, remove a circular patch of grass 4 feet in diameter surrounding the planting hole. If the grass creeps back later after the tree is well established this will not matter. Dig a planting hole 4 to 8 inches wider than the width of the root ball of the tree and to the same depth as the root ball of the tree (no deeper!) Planting trees too deep is one way to kill them. Test the drainage. Here is the method: Fill the planting hole with water and letting it drain out. Then fill with water a second time and this time place a yardstick across the top of the hole so it touches the level of the water and make a note of the time. Come back a few hours later and measure the distance from the stick to the top of the water. If the water in the hole drops at the rate of at least one quarter inch an hour, drainage is sufficient. If not, find another planting hole or alternatively build a raised bed. Your raised bed does not need to be very high. Here is how to build, fill and plant it: Four inches is tall enough and four feet square is wide enough. The easiest way is to build it out of redwood. Purchase lumber that is 8 inches wide to allow 2 inches on top for irrigation and mulch and two inches to extend down into the ground. The top of the bed should be level. Fill the raised bed 4 inches deep with top soil, making sure to mix some of this with the top few inches of native soil so you do not simply dump it on top, thus creating a hard horizon in the soil. Then dig straight through the earth in the raised bed into the soil below to make your planting hole. The top of the root ball should be at the top of the soil in the raised bed (that is 4 inches above the surrounding soil outside the raised bed), with two inches above that inside the raised bed for watering and later mulching. If the soil is heavy clay and it is compacted due to alkalinity, throw about half a coffee can full of gypsum in the bottom of the hole and combine it with the soil in the bottom of the hole. This will improve drainage. Place 3 or 4 slow-release landscape fertilizer pills or packets, such as Nutri-Pack,http://johnsonsway.com/nutri-pak-vs-tablets.php so they will surround but not touch the tree roots around the edges in the bottom of the hole. These will feed the tree for the amount of time stated on the package. Now remove the tree from the can and place it into the hole. Refill the hole with the native soil that came from the hole and press it down with your hands, not your feet or you will over-compact the soil. (Never amend a planting hole with compost or planting mix, unless planting something like a camellia that needs special soil or unless your soil is something akin to beach sand.) Make a watering basin. (In the case of a raised bed, it will serve as the watering basin.) Soak the hole deeply by laying the hose running slowly on top of the ground and allow the water to slowly penetrate the ground to the bottom of the hole and beyond. If drainage is good fill the planting hole with water more than once. Water every day for three days, three times a week the following week, twice a week the week after that, once a week for the next year or two. Once the tree is fully established you could can stretch out irrigations so you are watering deeply in warm dry months once a month, none in winter unless the weather is hot and dry. If planting in clay you might be able to water less than this. The situation you outlined suggests to me that part of the problem was either too little water or too much. Fertilize 3 times a year for the first 2 or 3 years. After that, fertilize the entire root zone once a year in March with all purpose balanced fertilizer. This should be sufficient until the tree is full grown. Eventually in most cases no fertilizer will be needed after a tree is full grown. However, in a case such as yours where the tree is surrounded by pavement, fertilizer may always be needed.

      Reply
  2. Thanks so much for your prompt response and expertise. I am so happy to see someone who shares so many people’s passion for plants and trees. On the Australian Weeping Willow Geijer Parviflora, I actually ran outside and measured it. It measures 51 inches from the east side of the bullnose brick wall, and 41 1/2 inches from the bullnose brick from the south.

    On the Jervis After Dark by the pool, it is about 8 feet in a cutout away from the pool.

    I will be taking photos about every six months to visualize the growth. Today I watered them with vitamin B-2 and Fish Emulsion. The Tipu trees, Australian Willow, and Peppermint Willows were planted on 6/26/11 and I can see that the Tipus grew about a foot, and the other two have gotten new shoots, but no height. Let me know if I labeled the Australian and Peppermint Willows wrong, because actually I forgot which is which LOL!

    ALSO PAT, SEE THE ATTACHED PHOTO. I saw this tree and love it, but don’t know what it is. I didn’t want to go pull branches off and take it to the nursery. Can you identify this tree and let me know?

    Reply
    • The photo you sent me shows a purple-leaf mimosa tree or silk tree (Albizia julibrissin ‘Summer Chocolate’), which is more frequently grown in the Deep South and Florida than here. It has yellow blooms instead of white or pink blooms like the green-leafed mimosa/silk tree varieties usually grown here.

      Regarding fertilizing. Fertilize trees in the basic landscape by spreading a balanced granulated fertilizer recommended for landscape trees under the drip line surrounding the tree in March. Spread just before rain or water in thoroughly.

      By the way, B vitamins do nothing beneficial for plants. This was proved by scientific tests many years ago. Go ahead and use up your bottle, but in future don’t waste money on this product. Ever since the testing was done, B1 transplant fluid has been on nursery shelves simply for the purpose of gyping the unsuspecting gardener. The people who make it know it does no good but gardeners still believe it does and nursery persons recommend it for transplanting because they don’t know the facts. If you want to use a product for stimulating plant roots when transplanting and planting, the thing to get is humic acid and products containing humic acid. These are the best transplanting fluids ever created and they actually cause a massive proliferation of roots. When making cuttings of plants, use Dip ‘N’ Grow™ according to package directions. This product is also very effective when used correctly.

      Reply
      • How are these trees in zone 9-10. It gets pretty hot out here like over 100 in summer for at least 3 mos. I know that they’re invasive right (I know the green one is), and the green one like my neighbors around the corner makes a humongous mess when leaves drop. What do you think about this tree being on a front lawn?

        Reply
        • Yes it can take heat. A great horticulturist once said to me, “Plants are not a forever thing. Tell folks to plunge in and enjoy plants and if they find they don’t like something, yank it out and plant something else.” Albizzias don’t live very long. They take heat fine. This one—’Summer Chocolate’— is hard to find. If you like it and can find one, why not grow it? If it dies young, then whatever bad habits it had while it was alive will no longer be a nuisance. It might leave a few seedlings, so much the better. I have known several albizzias growing in lawns and they did fine.

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  3. Sean Cleary August 25, 2011

    What cities have used this tree (Agonis flexuosa=Aus. Peppermint tree)?
    Where in the southland or inland empire can I find one to look at? to purchase?
    I have heard that they are fragrant after a rain shower. Is this true?

    Reply
    • Peppermint willow (Agonis flexuosa) is a good choice for street or garden use wherever temperatures stay above 27 degrees Fahrenheit. Los Angeles, Huntington Beach, and San Diego are three cities that have recommended and used this tree. It is listed in the first and later editions of the well-regarded reference book: “Street Trees Recommended for Southern California”, published by Street Tree Seminar Inc. in Anaheim, CA: Al Epperson, President 1994. (to obtain a copy phone (714) 639-6516.)

      Due to its many virtues, Agonis has become one of the most popular garden and street trees in Southern California. Foliage smells strongly of peppermint if crushed. Though some people report it is fragrant after rain, I haven’t experienced this characteristic myself so cannot guarantee this claim is true. Also, some people have better olfactory nerves than others. Agonis is durable, drought-resistant, attractive and the leaves hang down like a weeping willow but it is more erect than a weeping willow (Salix babylonica) and casts denser shade. It is adapted to Sunset Zones 15-17 and 20-24, suitable for 5′x6′ parkways or 5′X5′ cutouts. It has no significant pest problems, and does well in poor soil, strong wind, heat, drought, or ocean wind. A specimen is located at 3537 Addison St. Pt. Loma, San Diego.

      Due to its popularity, virtually all large tree farms in Southern California now carry Agonis flexuosa. The black form (Agonis ‘Jervis Bay After Dark’) is somewhat smaller and less frequently seen but gaining in popularity. I suggest you visit your nearest large tree farm, tree nursery, or tree grower near you in order to see boxed specimens of Agonis flexuosa. (Phone ahead to make sure they have specimens in stock.) Your local Parks and Recreation Committee might know of an example growing in your town.

      Reply