Gardening Unplugged - Tree Talk, Just Look Up

Gardening Unplugged - Tree Talk, Just Look Up

with Tony Avent

By Published December 21, 2022

Shop for Trees at Plant Delights Nursery

During this Gardening Unplugged talk, Tony shows off some of his favorite tree species, discusses pruning myths and malpractices, and shares tips on how to save trees from land developers.

Trees and genera that Tony mentions in this talk:

  • Metasequoia glyptostroboides 'Ogon' (Golden Dawn Redwood)
  • Elaeocarpus
  • Euonymus americanus (Hearts-a-Bustin’)
  • Loropetalum
  • Celtis sinensis 'Green Cascade' (Chinese Weeping Hackberry)
  • Ginkgo biloba ‘Mariken’ (Dwarf Maidenhair Tree)
  • Carpinus betulus (Common Hornbeam)
  • Dendropanax
  • Taxus
  • Cercis
  • Lagerstroemia fauriei
  • Cercidiphyllum
  • Parrotia persica
  • Zelkova serrata ‘Goshiki’


To learn more about the air spading or root invigoration methods mentioned in this talk, Tony recommends contacting Bartlett Tree Experts if you are in the Triangle area.



Video Transcription

Several really interesting trees to note here - the alley above us is a dawn redwood and this is the gold leaf dawn redwood. Dawn redwood is a historic relic tree that was discovered in China back in the 1950s, so fairly recent. And a gold form of that was a seedling that was discovered at a Japanese park by one of our customers. So, these are the oldest ones in the US. This is a cultivar called ‘Ogon’, bright yellow. If you look at it from a distance, spring and summer, it's just brilliant gold. This is our counterpart to our native bald cypress. It is pretty much... for some people it's hard to tell apart because they are very similar. This is a deciduous conifer. Most of the conifers we looked at were evergreen, this one drops all its leaves in fall with all the deciduous trees and so it's barren all wintertime. Like our bald cypress, it really loves water. You could plant this at the edge of a pond, and it would be happy as a clam, it'll grow faster. Up here it slows down the growth but obviously they're doing extremely well. A tree to note down here at the end, you can see the tree with the gold tip. This is a one of the zelkovas, a beautiful tree, one of the gold leaf forms. You'll see some zelkovas, we've got a beautiful one in the front we'll walk you under. Just a beautiful vase shape and you're seeing these used a lot in cities because the shape is just so incredible, and they don't take up a lot of room and are extremely easy to grow. All right, we'll look at a few more.

One of my favorite trees, of evergreens, is a plant called elaeocarpus. This is one you will never find at your garden center because it's not supposed to grow here. This is in the rose family, it flowers... it just flowered a month ago so it flowers in the middle of August. If you're a beekeeper this thing is a godsend because there are not many trees in flower in August for the bees and this tree will actually buzz there are so many bees on it. Just this delicious fragrance. When the leaves drop, because remember I mentioned evergreen trees dropped their leaves, they just drop them all at once, this drops its leaves in June, and they are brilliant red. So, you go out one day and in the middle of late spring and all of a sudden, you've got this beautiful carpet of red all over the ground which is really amazing, and the leaves are small so they're not really a problem.

Q: Do you actually get up all the leaves that fall?

A: Oh, great question. So, the question is - of raking leaves; Do we rake leaves? We do because we have really valuable plants underneath that could easily get smothered, and we just take them and move them and compost them and then bring them right back. So, you don't ever want to get rid of your leaves because your leaves are your fertilizer. So, you can take, it there are a couple options, you can take them out, you can mow them put them right back. We have a really nice compost facility on site, so we just take them there, compost them, then bring them right back in. So again, the leaves are your fertilizer so don't be caught up on being too neat.

Q: What about oak leaves?

A: Oh, fantastic, fantastic fertilizer. It doesn't matter what kind of leaves they are.

Q: Grind them up?

They're much better because they're big so as long as you don't have anything underneath them, they're fine to leave them but if you garden underneath them yeah it will smother other plants and that becomes a real problem.

An interesting tree behind us another evergreen conifer that I think is really incredible, this is a redwood tree from California. Which also, we're not supposed to grow here but they... if they're... actually if you buy the right cultivar, they're fine. So that will get up hundreds of feet tall, it's a massive tree. This really old one in Raleigh, over by Meredith College, that's been there now, I think, 70 years that's just absolutely massive. So, if you want one in your garden and you're not going to move in a while move soon that is a really neat plant.

Let's see actually let's walk up here I got a couple of interesting trees before we head over to the other garden.

Now here's another neat group of trees that most people think of as shrubs, these are euonymus. Most everybody thinks euonymus is either a ground cover or a shrub to be clipped. There's several tree euonymus that are amazing. They're just starting to fruit up, they have beautiful red fruit that split open like the old native Hearts-a-Bustin'. I think they're incredible group of plants.

Now we mentioned earlier the loropetalum, here's one you can see a little better. So, there's the same plant, again you see, nice small tree, not a shrub.

One of our favorite trees is this one right here - this is a Weeping Chinese Hackberry. This is Celtis sinensis 'Green Cascade'. When this is young, it's one of the fastest growing trees that you can grow - 10 to 12 foot a year. It's Hackberry, Chinese Weeping Hackberry. This was developed actually over in Chapel Hill by Camellia Forest Nursery... just incredible. So, if you've got kids or grand kids, when they're born, plant one. By the time they're able to climb, it'll be climbable. It's just an absolutely amazing tree.

And one I wanted to show because it's so unusual is this - this is another Japanese maple. So, we talked earlier, I showed you one that was very upright, this one makes this dense mass. That's never been pruned, that's what it does. It does that on its own. So, you can take just species and just by selecting the cultivar you can have a completely different form, and this looks like this little cloud pruned Japanese ball, which is just crazy. We'll cut through here.

This is a dwarf ginkgo. That's one called 'Mariken' so that's now about 15 years old. So, you can see dwarf means different things. That one I would consider a dwarf now we also showed you, back there, a hornbeam, the Carpinus betulus. Okay, this is a hornbeam - the same age as the one I showed you. So that's the cool thing about selecting cultivars and that's what some crazy plant people do is they select these amazing dwarf cultivars that you can fit in any type of garden no matter how big it is. Anybody ever heard of a styrax? Anybody knows what that... okay you heard of styrax. Alright, behind you is a dwarf styrax. That's as tall as that will ever get. So normal styraxes are in the 12-to-15-foot range. So, it's really neat when you start collecting the different forms that people have found through the years and named.

Alright, we'll look at a couple more. So, we looked earlier at plants that have been pruned so that you couldn't recognize them, and another example is the plant behind us. This is the genus Taxus or yew. So, if you're from up North, the only yews you know are the little clip green meatballs. This is what they use look like if you don't clip them. They are trees. They are not little bitty plants. Yes, there are dwarfs but the majority of them are just clipped within an inch of their life. The bark on this is absolutely incredible. So that is the Chinese yew and one we highly recommend. Behind us over here is another neat evergreen - this is a first cousin to an English ivy but it's a tree and it's called Dendropanax.  Panax is generally the root of the word that is used on any tree that's related to English ivy. This one never runs; it is a wonderful evergreen tree. So again, trying to fit different sizes in of trees is really neat.

Thank you! Hey how are you today?

Yeah, good to see you. Thanks for coming out.


It's a little crazy.

So, we talked about hemlocks and years ago I was told you could not grow the native hemlock here - the Canada hemlock. So, we planted one and there it is, not growing, 32 years later. Now the really neat tree behind us is one of our favorites. This is also a favorite of the late J.C. Raulston, that's a crape myrtle. That is Lagerstroemia fauriei - that's the Fauriei crape myrtle from an island off the southern coast of Japan. It [becomes] a 60-foot tree. So, it's not a plant. I know people have this thing they feel like they've got to behead their crepe myrtles, that was started by Southern Living Magazine back in the 1970’s where one of their editors wrote that it made crape myrtles flower better if you cut the old flowers off, which it does not. But once they started it, one neighbor cut the flowers off next neighbor had to outdo that neighbor and the next thing you know they're beheading the things. And to this day crepe murder continues. It's just absolutely bizarre but what an amazing plant if you leave it alone and let it grow.

Q: When was that planted?

A: That was planted in 1991 as a seedling.

So, they grow fast if you take care of them. Another beautiful tree that I love, I love for the cherry-like bark, this is also a lilac. So, it's another tree lilac - this is Syringa reticulata. This is one called 'Ivory Silk'. Beautiful clusters of white flowers and again, considering lilacs don't grow here, it's growing pretty well. That was started from a four-inch pot.

A plant that you will find at some of the garden centers is this plant. This also from Japan and it's interesting how they name plants. We passed by a number of Red Buds. Red Buds are a member of the genus Cercis, c-e-r-c-i-s.

This is the genus Cercidiphyllum which means - plant that looks like a red bud. It is not a red bud, it's not really related to a red bud, but the leaf looks like a red bud. Now normally the tree grows upright but this is a beautiful form called 'Pendula'. There are many named cultivars now that are weeping. These like moist soils. If you plant this too dry, it'll lose its leaves in June. It won't kill it, but each year the leaves hold on a little longer. But the cool thing about it - when it turns fall, the leaves smell exactly like cotton candy. You will walk through the garden and [it’s] just like you're at the fair. The whole fragrance of cotton candy is amazing. So cercidiphyllum, really neat tree.

So, on the patio, we looked at the crape myrtle, the Lagerstroemia fauriei, this is a dwarf for you. So, this only gets to 30 foot tall where the other one got to 60 foot. And this is a cultivar released by the Raulston Arboretum called 'Townhouse'. Really an amazing little plant. Now take a look as you come through on your left - the large trees in here with the huge trunks. Anybody recognize those?


Walnuts. Black walnuts. And we all know if we read books that you can't grow anything under black walnuts. Well as with every gardening myth there is a grain of truth that started that myth. The walnuts release a toxin called juglone and it does kill a fair number of plants. The toxin comes from the leaves, the nuts, and the roots. Okay, pretty easy, rake up the leaves, rake up the nuts, you got that part solved. So, what do you do about the roots? We found, in our experiment, if you do not use chemical fertilizers and poison your soil and kill all the microbes, the microbes break down the juglone and then you can grow everything underneath it. So, we were ready to cut these down, but we said let's do an experiment and let's find out is that real and it turns out we've been able to save these magnificent trees.

A couple more and we're stopped. Really another neat one - this is called Persian ironwood. Beautiful, mottled bark like the plant we saw at the beginning, but it does not seed around does not become a problem. Persian ironwood is a cross, of course, from Persia which has now had a name change it's called Iran. This is one of the few Iranian trees we actually grow. It is absolutely amazing. It is one of the last trees to lose its leaves, sometimes as late as November and generally bright yellow. It's just... generally this thing glows like a ginkgo when it goes deciduous. It is an extraordinary tree.

Q: What's it called?

A: Parrotia is p-a-r-r-o-t-i-a. Parrotia persica from Persia. An outstanding tree, I can't say enough great things about this. That's a tree to me that should be in every single garden.

So, these are those hybrid Magnolias and in spring... late spring... late winter, early spring, it is absolutely amazing. The whole garden, when they fall, is covered with these beautiful pink, purple, white, and yellow petals.

This is again zelkovas are used a lot in commercial landscapes now because the bark is so great the form is so great just everything about the tree is incredible. This one I love - this is a variegated leaf form called ‘Goshiki’. I think if I had to grow one tree this would be it. It's just an absolutely splendid plant, it's fast growing, it just is.... you just can't beat it.

So, I'm going to stop here. Do you have any questions? I know that's a lot of trees. Probably more than we planned on but... Yes?

Q: Do you know who came up with the tree protection signs? Does that really save the trees?

A: Ah, great question. The question is about the tree protection signs that you see. That really happened in the late 70s. Developers didn't understand what we talked about at the beginning of where the tree roots were. They would drive equipment over the trees and to them as long as the tree was left standing, they could actually sell the lot for more. They could call it a wooded lot. I remember in... right across from the old Rex Hospital on Wade Avenue they built a huge development there, this is back in the 80s, and there was a big article in the paper - Trees Dying in Development, Developer you know Puzzled. I was like… and I told my wife five years early, I said - every tree in there is going to be dead within five years. It was no puzzle. They drove all over the roots of the trees. They didn't take care of them. So, what the idea was - because developers are interested in one thing, making money, getting out as fast, they don't give a damn about the trees - was to put those in the root zone so that people would not drive the equipment in there. I drove by some signs last week; they're now putting them within a foot of the trunk. That's one of the most worthless crap there's ever been. If again, you go to the edge of the drip line and you go out that far again. If you don't, you have done no good.

Q: So those trees are going to die.

A: Those trees will 100 percent die, yes. Yeah, it's people who buy wooded lots from developers and don't know what they're doing, they're just, because they're going to have to be the ones to foot the bill for those trees. And it generally will take five to ten years for those trees to die. Now, can you come back in and resuscitate those trees? Yes, it's all an understanding what happened and why. So, when we built this part of the garden, we came in here with a tractor mounted tiller and we tilled off 90 percent of the roots on every tree in here. We did not lose a one because what we did, we made sure the soil nutrition was correct first. We went in we added everything was organic we made sure we had good microbial activity. We made sure that once we tilled it, we irrigated it regularly it never got a chance to dry out. So, we had good microbial activity good nutrition. Trees came right back. They regenerated every single root. So, when they go in the developers go in yes you can come in behind them and if you do it quickly and you do everything right. You can bring back every single one of those trees, without question. One of the best things that's ever happened was the invitation of invention of root spading treats um air spading it’s called. Everybody heard of air spading. Air spading is amazing. It's where they... it was actually from the military, it was adapted, they used it to find landmines. So, they would go in where [there were] landmines and they blow high pressure air. The air blows all the soil out and you can see the land mines and you can take them out. So, they can go in now around trees that have been compacted in new developments go in and blow the soil out and it basically puts air in then they can add compost put it right back in and the roots just explode. So there so there is a way now where we did not have it before where you could solve those problems. You absolutely can now.

Q: And there are arborists that would have that equipment?

A: Yes absolutely. I know Bartlett Tree does, I don't know how many other...

Q: What is it called?

A: Air spading.

Q: So, if I have one oak tree, if I get in touch with the developer and say here's what I think you need to do if you want this tree to still be around...

A: Yes absolutely, yeah or call Bartlett first and get them to come out and give you an evaluation and then take that to the developer and say - hey, here is the leading tree authority in the United States, here's what they say you need to do and here's how to do it. I would start there. But it is incredible it is a game changer for preserving old trees and trees that the developers just didn't give a damn about. And we have to hold developers’ feet to the fire because they really don't care about the trees. All they care about is leaving them standing until they sell you the lot. I mean I hate to be skeptical but that's really sadly the case.

Other questions? Great questions.

Q: Yeah, a real plebeian question...

A: Okay

Q: I got suckers and pruning suckers and well, I've got crepe myrtles and they sucker like crazy, and I've got cherry trees and they sucker like crazy, and I spend all my time cutting down these suckers. I've tried so much, and I mean before I did the Sucker Punch, I would have to do it two or three times yeah and look at these on the cherries um like little Pearl that looks like a pearl on them.

A: Yes, so the question there are suckers that come up and not every tree suckers, a few do, but more than others. Generally, that is due to a stress in the tree, not a hundred percent, but most of the cases that's due to a stress. The key is when you cut the sucker back cut it all the way flush. If you don't, if you leave a half inch, it's going to just continue to sucker. If you cut it all the way back, it will actually heal over, and you will never have another sucker.

Q: You cut down into it a little bit?

A: Yeah, every plant... let me... I'm trying to see how I could... let me see if I can show back here. All right, so if I look on this tree right here...when you cut a tree the key is knowing where the healing tissue is. Let's see if I've got any clippers with me, probably don't, but all right. So, if you're cutting and you cut here - and you prune it there - there's no healing tissue there. That will never heal, unlike your finger, it will never grow back over. If you look at the base here, you can see those wrinkles. That is the healing tissue so if you cut right there, that will heal over and then you will never have a sucker. That's the key is that first cut is done correctly.

Q: Are all plants the same way?

A: Yes, all plants. All plants are the same way. Yes, you have to find that healing tissue, that is the absolute key. Now perennials, not as critical because they have a lot more healing tissue at each node. It's really on woody plants that this is critical but that healing tissue, you can always find that. You've got to cut back to that, don't cut it off because then you're cutting off the healing tissue, but cut right to it and that will actually heal over. And that's why things like crape murder are really dumb because there's no healing tissue. That will always remain an open wound for diseases to come in and damage the plants and that's not good. That's how we lose so many plants.

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