A Rock Garden Primer

A Rock Garden Primer

Part of Ep. 503 On the Rocks

Make the most of large rocks in your yard.  Jack Ferreri creates a rock garden by adding low growing and spreading plants.

Premiere date: May 31, 1997

TRANSCRIPT+
Wisc Gardener Transcript: 

Shelley:
You know, in many parts of Wisconsin, if you dig at all, you're likely to come up with some rocks. Now, here's a suggestion as to what you can do with those rocks. We're in the garden of Jack Ferreri. Jack, tell me what you did when you discovered this in your yard.

Jack:
Well, I had this great big rock. I cleared it out, it had a lot of honey suckle and such around it. I cleared it out, and was interested in gardening. I had all these rocks, so rock gardening seemed like a natural way to go.

Shelley:
Now, rock gardening plants are very special. Why, what makes them so special?

Jack:
Well, they're plants that come from mountainous areas. They usually come from above the tree line. And the conditions up there are very harsh. It's windy. Spring comes late and winter comes early. So, they're spring bloomers.

Shelley:
They're kind of ideal for Wisconsin.

Jack:
They're ideal for Wisconsin. And they're very low growing. There's a Columbine down there that's a lot smaller than most of the ones you're used to.

Shelley:
This is as big as it's going to get?

Jack:
That's right.

Shelley:
It's beautiful. Now, what do I need to do to plant these? Do I have to have a rock garden to grow these low-growing perennials?

Jack:
No, you don't. There's really only two things you need to be growing rock garden plants. One of them is sun. You need pretty good sun. And the other is that you need a soil that is pretty quick draining, you need to have a fairly lean soil.

Shelley:
What would that mean lean, then?

Jack:
Well, typically, rock gardeners grow their plants in a mix of roughly, one-third soil, one-third sand and one-third rock chips.

Shelley:
Okay, no clay, then.

Jack:
Right.

Shelley:
Now, you've got a wide variety of plants tucked in here and there. This one here looks familiar.

Jack:
That's a clematis. It's not one of those big hybrids you see all the time. This is a native species from out in the Pacific Northwest. It's just been sprawling over this rock. It wanted to sprawl the other way, but I've trained it up here.

Shelley:
I'm used to the ones that climb up the side of the house. This is as big as it gets?

Jack:
They get a little bit bigger, but not much.

Shelley:
So, there's some really charming guys. Well, if I don't have to have rocks, what else do I need, though, to keep these plants happy?

Jack:
Well, it's nice to have a variety of aspects, a variety of ways that the sun faces, and have things like this, this is a raised bed. And I've used some rocks to build it. It gives me a lot of different orientations. So, I have some plants that want full sun, they face the south. The plants that just want the morning sun, I've got that, too. This is a little Draba. It's a little spring-flowering alpine.

Shelley:
It's charming.

Jack:
I put it in there when it was a very small plant. And as you can see, it's spread out and it's now filling in the crevice quite nicely.

Shelley:
So, that's really one of the issues of rock gardening, then. Well, even if you're not using rocks, these guys are so small, we have to something to raise them up, or they're just going to be lost in their own garden.

Jack:
That's right. If you plant them among larger plants, then you can't see them. And when they're down very low, it's hard to get down to them.

Shelley:
So, placement is maybe as important as lean soil and full sun.

Jack:
That's right.

Shelley:
Now, what is this? This is gorgeous.

Jack:
This is a Daphne. Most Daphnes are three or four feet high, or so.

Shelley:
Yeah, mine is.

Jack:
This one is about eight or nine years old and that's about as tall as it's going to get. It get's a little bit wider each year.

Shelley:
Daphnes are evergreens, aren't they?

Jack:
They are. And that sometimes makes a problem, because this raised bed, that makes it easier for us to appreciate it, serves as kind of a feeding shelf for deer. And since that stays green through the winter, sometimes I get some damage on that. But it's tough enough, it always comes back.

Shelley:
So, eye-level for us and teeth-level for the animals!

Jack:
That's right.
Shelley:
Now, you say that we don't need rocks to do these plants. What about the mulch? It's almost a gravel you've got here.

Jack:
It's a pea gravel. You can get that from almost any stone supplier. And it's good to mulch with because it keeps weeds down and the foliage of these plants like to rest on stone because that's the way it is in its native environment.

Shelley:
Okay.

Jack:
If it rests on a rich soil, you get all kinds of bacterial and viral infections. We don't have to worry about those when we have the plants on stone.

Shelley:
So, even if we put these in a normal perennial bed, use a rock mulch.

Jack:
It would be nice to have a rock mulch, yes.

Shelley:
We've been talking about doing this without rocks. Obviously, in your yard, you have lots of rocks. Tell me what you've done.

Jack:
Well, I have a pretty good situation here. I'm on a natural slope. We're at kind of the bottom end of the slope now. And what I've done over the years, is I've built this garden from the original rock up to that far outcropping you see in the distance, there. I've terraced it. I have a range of sand beds, here, with plants from very dry areas of the world. Then I go back to regular rock garden plants up there that I have terraced with some natural limestone rocks.

Shelley:
You've really got a nice flow, here. One of the things that's fascinating is these plants are so small, you can plant so many varieties in one small spot.

Jack:
Right.

Shelley:
For instance, this bed over here is crammed with all sorts of little beauties. Can you give me kind of a tour of what I'm looking at, here?

Jack:
Sure. Most of these plants are pretty small. They don't get very tall. That's nice for getting a lot in small spaces, but you don't want it to become too low. So, it's nice to have an occasional plant that's taller.

Shelley:
It kind of breaks it up.

Jack:
Right. This is a Dwarf Conifer that gives it a little bit of height. I have some others that are even a little bit taller. There are a lot of very small plants in here, too. Here's a Dwarf Veronica. As you can see from last year's seed heads, it doesn't get much higher than five or six inches.

Shelley:
It's almost a mat.

Jack:
Yes. And it seeds around just a little bit.

Shelley:
What's the plant next to the Veronica?

Jack:
That's a member of the daisy family. It's called an Erigeron. It's a spring bloomer-- not a very big flower, but it has kind of interesting foliage.

Shelley:
Okay.

Jack:
I've got another Columbine, there. This one is pure white. It stays very low and seeds true white.

Shelley:
It has a beautiful, delicate color to it.

Jack:
Right. Up against the rock, is a little Sedum that you can see has probably been there ten years and is covering quite an area.

Shelley:
That bright green creeping plant?

Jack:
That's right.

Shelley:
It's beautiful.

Jack:
And then I have a number of Phlox cultivars in this bed, in different colors. They seed around and put on quite a display.
Shelley:
Great. Thanks, Jack. So, you can get a lot of texture, color and variety, whether you have a large garden or a very small space.

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