Gardening Unplugged - Gardening with Conifers

Gardening Unplugged - Gardening with Conifers

with Tony Avent

By Published August 2022

Join Tony Avent as he takes guests on a tour of some of the amazing conifers at Juniper Level Botanic Garden during our Winter Open Nursery and Garden Days in February 2018. Gardening Unplugged is our series of free classes presented by JLBG/PDN staff during our Garden and Nursery Open House days. These are 15 - 30 minute discussions walking through the gardens, focusing on seasonally prominent topics, plants, and garden design ideas.

Conifers featured in this talk:

  • Abies balsamea (Balsam fir)
  • Abies Bornmuelleriana (Turkish Fir)
  • Cryptomeria (Japanese Cedar)
  • Chamaecyparis obtuse (Hinoki False Cypress)
  • Chamaecyparis obtusa 'Kanaamihiba’
  • Chamaecyparis pisifera ‘Vintage Gold’
  • Chamaecyparis nootkatensis (Alaska Cedar)
  • Boulevard cypress
  • Cathaya argyrophylla
  • Sciadopitys (Japanese Umbrella Pine)
  • Keteleeria
  • Juniperus rigida
  • Taxus (Yew)
  • Taxus chinensis
  • Juniperus horizontalis ‘Blue Rug Juniper’
  • Arborvitae
  • Tsuga canadensis
  • Woolly adelgids
  • Podocarpus macrophyllus
  • Torreya grandis
  • Thujopsis dolabrata


Video Transcript

Today we’re talking about conifers in the garden. I’ve always been a fan of conifers in the garden and a real turning point in this region was the late J.C. Raulston. Back in the late seventies when he got the arboretum started, one of his stated goals was to find conifers that grew in the South because all of the books said conifers don’t grow in the South. Well, of course that was sort of silly because we have native confers, like the pines we see out here. Conifers are very prehistoric plants. They evolved before plants discovered how to flower. Conifers idea of flowers are what we call pine pollen. All conifers are wind pollinated. No insects have anything to do with it. The pollen from the males has to fly through the wind on days like today. That’s what distinguishes conifers from other plants.

Conifers Actually Do Grow in the South

One of the things that J.C. found was that yes, there were a lot of conifers that do very well here in the South. We’ve still got a very good collection of his work at the arboretum. We’ll look at some of those today. We’ll focus on several different genera. Probably the genera that’s considered the hardiest here are the firs. Because everybody thinks of furs in terms of the Balsam fir or other firs that we use as Christmas trees. But the reality is there are a lot of really good firs for this area. One of my favorites is this one here; this is the Turkish fir, Abies bornmuelleriana. This is one we grew from seed that is now a 15-year-old plant. It grows about a foot a year which is the same rate that a typical balsam has. The Turkish fir is extremely adaptable to this area. So, it’s sort of surprising that more people aren’t growing this and it’s simply because there’s just not a lot of availability in the East. You pretty much have to buy seeds or buy the plants from the west coast. We’ve been trying to get more nurserymen to really start doing that.

"Dwarf" is not a Size

A group that’s very common are the cryptomerias or Japanese cedars. This is one right here. The Japanese cedars are typically very tall trees, 60 to 100 feet. There are a lot of what’s called dwarf conifers. Dwarf is one of those words that has a very interesting definition. Dwarf means that somebody has a taller one. Dwarf is not a size. So, you have to be aware of that when you are buying. This is a dwarf but it’s going to mature out in the 15-to-20-foot range. We have other dwarfs you’ll see that will mature from 1 foot to 4 foot tall so there are various sizes of any conifers.

Another group is the false cypress or chamaecyparis. Chamae- means false, -cyparis, cypress. You’ll see a lot of these but there are two basic species that are very common. Chamaecyparis obtusa, common name hinoki cypress. And there’s Chamaecyparis pisifera which is called sawara cypress. Basically, the sawara are just much faster growing. This is one of the hinokis and again, this is a dwarf. This is ‘Confucius’, that’s sold as a dwarf and most catalogs are going to tell you that it matures out at 4 to 6 feet. Well, not really. When we see sizes in a catalog, we typically multiply by 3. That’s going to give you the actual size.

We talked about this chamaecyparis, here’s the other chamaecyparis. This is a sawara cypress, Chamaecyparis pisifera, this is one called ‘Vintage Gold’. We bought that and the book said it would mature out at 6 feet tall. If you go in the front garden out by the garage, you’ll see a boulevard cypress. That’s another one that is sold as 6 feet tall, ours is now over 30 feet tall.  When you plant these, you have to be very, very careful to get them in the right spot or they’ll eat your house or whatever.

Now, one of the more unusual conifers is the plant right here in front of the house. This is a very rare conifer it is what’s known as a monotypic genus, means there is only one of them. This is the genus Cathaya, Cathaya argyrophylla. It’s a native to China, it was one of their very rare sacred trees. It was first brought into the US about 20 years ago. This is one of the very first ones. We were told it wouldn’t tolerate heat or cold. And actually, it has tolerated both quite well. Still not a lot of it around. It looks very similar to a Japanese umbrella pine, sciadopitys, but it’s actually more closely related to a Douglas Fir. It’s turned out [to be] a really good plant. Obviously if I was growing that again, I would plant it in a different place now that I know it’s going to live. Because we really assumed it had no chance.

Now, this is one of J.C. Raulstons favorite plants. This is one he really touted. This is keteleeria. Keteleeria is another Asian plant depending on your taxonomists, anywhere from 4 to 6 species. A fast-growing plant, a beautiful evergreen. It has fantastic cones on it. If you come in the fall, you’ll see the amazing, amazing cones. The one that JC originally grew opened very early in spring and would always get blasted by the frost but that was simply one bad seedling because we’ve never seen that issue here. In China, they actually eat the needles. They served them to us one night, sauteed, and it was like chewing on hard plastic. I believe I could’ve found things more tasty than keteleeria but they are eatable.

West Coast Conifers on the East Coast?

This is also another chamaecyparis of course, depending on the taxonomists, they’re always moving this stuff around. This is native to Alaska. It’s called the Alaska cedar, Chamaecyparis nootkatensis, after the Nootka peninsula, out on the west coast. Typically, we can’t grow the west coast conifers very well. We can grow a few of them. But this is fantastic because, on the west coast, it grows in swamps. Our problem with bringing plants from the west coast typically is that they don’t like our summer rains. This one, since it lives in a swamp, doesn’t actually mind. Now the growth rate on west coast conifers, or on all conifers, is much slower in the East. What happens is, the heat of the day, the sun of the day, builds up energy in the plant. One of two things happens at night. If the temperature is low enough, all that energy absorbed during the day goes into growth and you get a fantastic amount of growth. If the temperature at night stays high, as it does here in the summer, all that is used up just keeping the plant alive so it’s not able to go into growth. So, our growth rates are about one third of what you would see on the west coast where it had cool night temperatures. So, when you go out there and somebody says this is 5 years old, back here it is going to be about a third that height in the same timeframe.

And again, you’re looking under a false cypress. Just look at the size of that and again, we bought that as a 6-footer. This is what happens when you put these right by the house and then next thing you know you’ve got a problem. We decided instead of taking out, we just limb it up.

Here’s another hinoki cypress. Now this is very interesting, what you will see on a lot of the dwarves because they were originally a mutation of tall plants. Plants actually will often mutate back. And if you don’t realize its mutating back, your plant will get taller. 'Kanaamihiba’ matures out at about this tall. This one actually mutated and did not get cut back so this is the original plant from which the dwarf mutated. When you’re out there and you’re looking at your plant, and you see one going a little wacky, that is the mutation and the mutation, being more vigorous, it’s actually going to kill off the original.

There’s a lot of junipers, we certainly know those. This is Juniperus rigida. This is a plant we see occasionally. I love it because it’s very architectural, it’s very open, it’s sort of spooky looking, very sharp. And this is an Asian native to China, Japan, and parts of Korea. You’ll see several as we walk through the gardens today.

Now I mentioned about the Japanese cedars and dwarfs. Here is an example of a dwarf dwarf. That is probably mature size. This is probably now about 20 years old. This is ‘Osaka Tama’, and that’s never been pruned. That’s its natural size. You can find dwarfs that are what we kind of think of as dwarfs and then other dwarfs you have to research and look at the size.

The chamaecyparis are one of the most shade tolerant of all the conifers.  Most conifers really need full sun but the chamaecyparis can do really well in a light shade, not a deep shade, but a light shade.

Another wonderful genus are the podocarpus and we typically see podocarpus being used much further in the deep south because a lot of the stuff that is in the trade commercially is not winter hardy here. The plant to grow here is Podocarpus macrophyllus and these, we’ve had no problem with any of the winters. And these are very upright. Some people love limbing them up because the bark is really attractive on these. They’re normally male and female but there are self-brooding forms. And the fruit on these is fascinating. Some of them are blue and some of them are red. They look like balls with little strings hanging out of them. Really amazing plants.

Q: What is the name of it again?

A: Podocarpus.

Podocarpus macrophyllus is Chinese, there are also some podocarpus from New Zealand that will actually grow here. Those are going to generally going be a little smaller than these. But these are nice, fairly narrow. You can use these when you need something that is not as wide as the other cypress.

You Have to Love Yews

A couple of other genera that we haven’t looked at yet – one is the yews. This is the genus Taxus. If you originated up North, you know that because down here we use Japanese Hollies for foundation, up north they use taxus. Taxus is a very interesting plant. The original ones were normally fairly tall and people through the years have selected dwarf forms and variegated forms. This is one called Aurescens Nana ‘Rezek’s Gold’. It will get a little bit taller but that is close to mature height, but the spread is pretty big. The spread is going to be 12 to 15 feet. The books say that taxus don’t grow in the South. They do grow fine; they just need well drained soil. They’re not very tolerant of very poor drainage. This one, when it comes out in the spring in about another week this will be brilliant yellow, just screaming yellow. The old growth down below that will stay green and then gradually over the summer the color ages to green.  A really great plant and they are very useful around here despite what the books say.

Here is a genera we haven’t looked at yet, this is torreya, Torreya grandis. This is the nutmeg tree, and this is a very close cousin to the Keteleeria we saw in front. This is actually from seed we collected on an island off the coast of Korea. The torreyas do very, very nice. Wonderful soft needles. The keteleeria has very rigid needles, these are much softer. When they get large, they do develop a fruit that is highly eatable. You would see people over in Korea with big baskets just picking up the fruit by the thousands that they take home to use.

The Key to Choosing Spruces is Elevation

We also have not looked yet at spruces. There are also a large number of spruces that do well in this area. Again, despite what the books say. Many of the Asian spruces, some of the US native spruces. The key is looking at elevations. If a spruce grows at 9-10 thousand feet elevation, then it's not going to grow right here. If it grows at low elevations its generally going to do very well.  Spruces are really grown for their beautiful cones which can be in the brownish reds into the blues, just amazing, amazing colors.

Now we looked at yews a minute ago, that’s a wild yew. That giant one over there. That’s Taxus chinensis. So that’s what yews normally look like, they don’t normally look like the foundation shrubs that have been selected for people to buy.

Now here’s another cryptomeria, this is one called yellow twig. I don’t know why it’s called yellow twig because there’s nothing about it that’s ever yellow. But again, this is a dwarf. So now, this is probably 20 to 25 feet where, again, the original would be 60 to 100 feet.

You’ll see here, this is another of the firs. This is the one that JC Raulston really promoted. This is the Abies firma is also a nice one. Very different look than the Bornmueller fir that we looked at around there. It doesn’t quite have the typical fir look which is why I prefer A. bornmuelleriana.

A couple of other plants for the shade, one is the hemlocks. There are actually a large number of hemlocks that do very well down here. From our native Tsuga canadensis. This is one of the Asians. We’re just trying to try some of the Pacific ones to see how they do but so far, we don’t have the woolly adelgid down here either, which is nice, which they have up in the mountains. But they’re looking at many of these Asian hemlocks as being much more resistant than our native is.

Behind that is another fantastic plant, this is another Asian genus called Thujopsis, is first cousin to arborvitaes which we really haven’t looked at, but it is much more shade tolerant than those are. Really a very attractive plant that we think should be used a lot more.

A couple of things we haven’t really looked at but I’m not going to drag you around the rest of the garden, I'll let you look at that. There are a couple of things, we looked at some junipers around there. What a lot of people don’t realize is the common junipers that we see, things like ‘Blue Rug’, those are actually US natives. A lot of people think that’s got to be Asian. Well, it’s not. It’s actually a native to the US. It occurs anywhere from Colorado up into Canada and across the entire northern US.

The other is arborvitaes. Arborvitae was always thought of as sort of a trash plant. That’s an East coast native. We’ve actually seen those in the wild in Tennessee and all the way into Arkansas. It's really quite amazing and yet when we talk about gardening with natives we don’t think about arborvitaes and blue rug junipers. But yet, they are native.

So, I hope that gives you a little bit of an idea on conifers today and if you’ve got any questions, please feel free and we’ll be around if you have any others. Thanks!

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