Show #35/6509. The Bones And Structure Of A Garden
Summary of Show
Water Management
Eric is excited, we're talking about WATER MANAGEMENT, also talking about many of the bones of the garden as well as the structure of a garden, thinking about what needs to be in place for the long run. Jim did a beautiful job, this garden is amazing. He had to think about many, many different aspects with this garden but one of the first things was the enormous elevation change and what he needed to do with all the water that's coming down this hill? Jim has built a beautiful system to deal with all that and Eric would like for Jim to talk about it. The first thing one must do is survey your property when you're building a garden, you've got to look at the drainage and make sure you accommodate that first or you'll be constantly having major washouts.
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Sizing Of Pipes
When you have a walkway, at some point it may become necessary to have pipes put under that walkway to manage water. If so one must think about the SIZING OF THIOSE PIPES. At the top there is less water, so he utilized eight inch pipes. (That’s the diameter of the pipe.) As more water is picked up on the way down a 12 inch diameter pipe is necessary to carry the water. As the water continues down, like at the top of this conifer garden Jim had to put an 18 inch diameter pipe in to carry all the water from the top already collected from all that land. Above them is another level and from the 18 above to here Jim had to size up to 24 inches.
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Stones And Boulders
When you get into those alpine settings, you'll normally find natural outcroppings of rock and they're like shelves of rock. All of the different conifers are surrounding them. What he likes to do is work STONES AND BOULDERS into the conifer garden because they are as interesting as the plants. Plants have different shapes and different forms and boulders are the same way. They have interesting form, different textures that will contrast. They also have great color contrast and the colors go with the tree trunks in the garden.
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Adding Plants To The Rocks
Jim has ADDED LITTLE PLANTS like the sedum angelonia around the stones. It's a great chartreuse color. Then for a vertical effect he’s used ogon that has a chartreuse effect along with the euphorbias. Mix that in with all the other textures and colors of the conifers and you soften the garden and rocks. Jim points out that they're standing in an area that has been softened. Jim points out another area where they have yet to soften the rocks. But all the little crevices in between will be filled with dirt, then plant little tiny ground covers. They will creep and sort of grow through those cracks and really create a lot of interest.
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Chipseal Pathway
The other thing you've got to think about, once you get it graded and put the PATHWAY in, is what surface are you're going to choose? Jim chose a special surface called Chipseal. Chipseal is a liquid asphalt, heated at a temperature between 150 degrees and 185 degrees. It is so hot it becomes liquid. First put down a base of 57 stone then pack that in to the fill dirt. After you finish that, you come in with this liquid asphalt, they use a sprayer that goes across the walkway, it's coming out in a liquid form and it goes on top of the base 57 stones.
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Planting On A Vertical Slope
Eric would like to discuss one more item before we leave today and that is PLANTING ON A VERTICAL SLOPE. Especially where we have significant elevation changes. We don't want to just go in and plop our plants into the ground, we need to think about how is that plant going to be best presented, particularly where we have a significant elevation change. And of course, this was something that Jim had to definitely keep in mind as that's really what this site is. Jim agrees with the steeper slopes here one must think about the plants that grow vertically and the plants that grow horizontally.
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Show #35/6509. The Bones And Structure Of A Garden
Transcript of Show
In this Episode GardenSMART returns to the north Georgia mountains to discuss garden design at one of the nation's largest estate gardens. Our journey at Gibbs Gardens through the painstaking and truly rewarding process of designing and building a new garden has been exciting. So much work has already gone into this project and there has been so much to consider along the way.
Jim Gibbs has been gardening well over half a century and began work on Gibbs Gardens in 1980. His lifetime of experience shows through in every aspect of his work. His work on the Inspiration Garden began several years ago and GardenSMART has been following this garden come together every step of the way. Today we take a look at the fine-tuning that makes for good design; everything from the placement of boulders, to walkway design, to correctly installing plants is what allows the finished product to shine.
Eric welcome Jim Gibbs back, thanks so much for joining us. Jim is pleased that Eric and GardenSMART are visiting again and following the planning and planting of his newest garden, the Inspiration Garden.
Eric is excited, we're talking about WATER MANAGEMENT, also talking about many of the bones of the garden as well as the structure of a garden, thinking about what needs to be in place for the long run. Jim did a beautiful job, this garden is amazing. He had to think about many, many different aspects with this garden but one of the first things was the enormous elevation change and what he needed to do with all the water that's coming down this hill? Jim has built a beautiful system to deal with all that and Eric would like for Jim to talk about it. The first thing one must do is survey your property when you're building a garden, you've got to look at the drainage and make sure you accommodate that first or you'll be constantly having major washouts. So, Jim had to start at the top where the manor house is. That is 150 feet above the stream that runs through the valley, close to the Japanese garden, which is in the lowest part of the garden. From there as it goes up it traverse the slopes up to the top at 150 feet, so that means a lot of water. They’re presently standing in a swale, a major swale, where all the water rushes down. All of these slopes in here are feeding water into this drainage area. So Jim had to figure out how to manage all that water. At the top, where the manor house is there is roof runoff and it runs fast. There are terraces, and patios; it hits those and runs off fast. There are gutters that have to empty onto those areas which mean fast runoff. There are walkways that go through, pool decks, all these things one must consider.
When you have a walkway, at some point it may become necessary to have pipes put under that walkway to manage water. If so one must think about the SIZING OF THIOSE PIPES. At the top there is less water, so he utilized eight inch pipes. (That’s the diameter of the pipe.) As more water is picked up on the way down a 12 inch diameter pipe is necessary to carry the water. As the water continues down, like at the top of this conifer garden Jim had to put an 18 inch diameter pipe in to carry all the water from the top already collected from all that land. Above them is another level and from the 18 above to here Jim had to size up to 24 inches. The 18 would have never worked, water would have washed this whole walkway out, the water would have overflowed over the walks and washed the plants out. From this 24 inch pipe right below it goes into another 24 inch pipe that's under that walkway. But below that with all the water now collected he needed to go to a 36 inch pipe to carry it on down to the stream, which goes into the valley. So, it’s important to think about your water. A few days ago, they had seven and a half inches of rain in one day. A lot of rain. If they hadn't put this size pipe in, it would have washed everything out. Jim designed it to be a wet weather stream, but it's also a dry stream. So you've got to make sure you place the rocks properly. The garden has to be thought out for drainage. Here they have a tremendous amount of water, but even a residence has roof water, it then goes into gutters, the gutters empty and that water needs to go somewhere. If the water crosses a walkway you will need some kind of pipe. The pipe size depends on the amount of water. It’s important to think about water management and drainage most of all. Eric feels that throughout Gibbs Gardens Jim has employed many different, clever ideas to slow down the flow of the water or to break up the water flow and divert it in different directions. Erosion can be devastating to a garden, so this is one of the items at the very top of the list that we've got to think about when building a garden. Importantly even if you don't have a steep elevation change like this, let's say that your garden is basically level you could still have problems with water pooling and creating wet areas where you're not able to grow what you want to grow. In those areas we've got to put in drainage, divert that water somewhere else so that we can keep the plants healthy and happy and have enough oxygen for the roots to grow and to protect the garden against erosion and washouts that could kill plants and remove valuable soil from our garden. In those level areas it’s often necessary to put drain tile in below the surface, maybe 18 inches, with gravel and four inch drain tile covering it along with filter cloth to let the water drain in. Be sure you find an outlet for the water or all plants can die because of too much water. Jim sees that all the time and it can be as dangerous a scenario as where you've got an elevation change and you're not able to get that water directed and moved away from your plants.
Eric remembers very well the first time he visited the Japanese garden here at Gibbs Gardens. One of the most impressive things was the way that Jim used boulders. And that is very important to good garden design and it's also been very important to the overall aesthetic of Gibbs Gardens. Eric would like for Jim to talk about his use of boulders in the conifer garden.
Jim likes to go back to examples, he loves to go to Canada because it's cool in the summer. When you get into those alpine settings, you'll normally find natural outcroppings of rock and they're like shelves of rock. All of the different conifers are surrounding them. What he likes to do is work STONES AND BOULDERS into the conifer garden because they are as interesting as the plants. Plants have different shapes and different forms and boulders are the same way. They have interesting form, different textures that will contrast. They also have great color contrast and the colors go with the tree trunks in the garden. If you look around these great colors are in all the tree trunks and the stones have those same natural colors too, which works very well. And brings all of that together making this drainage area look like it was always here. And it doesn't look like it was built to take out the water to the stream below, instead very natural. Jim thinks it's real important to select your rocks and boulders personally. He bought most of the stones from places like Jasper, even as far as Blue Ridge, Georgia, at different places. They probably got tired of seeing him coming because he was there to look for stones and personally selected all these stones. Some of these stones are 2000 pounds, a ton. They had to bring in a huge machine to lift them, had to strap them with seatbelt strapping to move them so they didn't scar the stones, then swing them around and position them. And he had to make sure that they got the shape and the form in the proper position. That takes a lot of time devoted to the stones. But, the worst thing one can do is just plop a stone down. The stone is going to be a part of the garden. One must first dig a hole to set the stone in, to make it look like a natural outcrop that's coming out of the ground. You may lose a third of the size of the stone because it's buried beneath the ground, but that’s important, it's got to look natural. They have just finished the selection of the boulders and they're all in place and now begun to put some of the softening elements around the stones. They’ll continue to put in little plants that will hang over the stones and hang down the sides and soften the stones.
Jim has ADDED LITTLE PLANTS like the sedum angelonia around the stones. It's a great chartreuse color. Then for a vertical effect he’s used ogon that has a chartreuse effect along with the euphorbias. Mix that in with all the other textures and colors of the conifers and you soften the garden and rocks. Jim points out that they're standing in an area that has been softened. Jim points out another area where they have yet to soften the rocks. But all the little crevices in between will be filled with dirt, then plant little tiny ground covers. They will creep and sort of grow through those cracks and really create a lot of interest. Jim thinks stones are just as important as plants. One might even have three stones in one place in their garden and create a little area to create some interest. It's just like adding a piece of sculpture. Eric agrees, when stones are done well it transports us to a different space. While standing in this conifer garden he feels like he's somewhere in the Pacific northwest, it doesn't feel like north Georgia. And the way that we use them is so important, selecting the right boulder for the right place is important, but then make them look as natural as possible. Naturalize the site. Jim did everything, he brought nature into the garden, it's naturalized, it brings everything in, it's not just isolated, it's a part of nature, it's a part of this overall environment, it's a part of all the plant collections. But these kind of areas have got to flow and work together. So it's taking a little section of one, then it joins another, nature is flowing in and out, it's a walk through nature from one area to the next, and that is what ties all the Gibbs Gardens together.
As one talks about the bones of a garden something that is so important to keep in mind, as well, is where the pathways are going to be. Pathways are the way we use the gardens, the way that we enjoy the garden. Eric knows that Jim put tremendous effort into planning the pathways before he started doing anything in the garden. Eric would like for Jim to discuss that with us. The first thing Jim does is design the pathways or walkways. You’ve got to make sure that when people visit a garden, particularly if on a hillside, you don't want to have too many steps because they can be very slippery and very dangerous. Anytime you have a steep slope, if you can take a longer distance and grade it and get the percent of grade to be much more gentle, it’s much more visitor friendly. What Jim had to do here was bring in over a thousand cubic yards, actually 1800 cubic yards of fill dirt. That's 300 truckloads of fill dirt just to get these walkways so one could gently walk on them and make the climb up or down without falling. That was a very important consideration.
The other thing you've got to think about, once you get it graded and put the PATHWAY in, is what surface are you're going to choose? Jim chose a special surface called Chipseal. Chipseal is a liquid asphalt, heated at a temperature between 150 degrees and 185 degrees. It is so hot it becomes liquid. First put down a base of 57 stone then pack that in to the fill dirt. After you finish that, you come in with this liquid asphalt, they use a sprayer that goes across the walkway, it's coming out in a liquid form and it goes on top of the base 57 stones. They then come right behind it putting these little tiny particles of 87 stone into the top of that liquid. That stone goes down in the liquid and it all comes together as the process goes on. The little tiny stones will have spaces between them but when they come in with the steel drum compactor, it compacts all of that together and squeezes it and mashes it together. What then happens is in the winter time, you don't have to worry so much about water getting in there. An asphalt driveway will often get cracks, then the cracks will open up when it rains, then when the temperatures drop and it freezes that causes the asphalt to expand and it pops open more, and over time gets worse and worse. This doesn't occur with the Chipseal. Another consideration here with the walkways is they could never get an asphalt truck in here or even a concrete truck so they had to think, what do we use? So this is a special process, it is one-fourth the cost of a concrete walk, it's one-half the cost of an asphalt walk and it looks much better. The gray color of the granite stone is the same color of the tree trunks all around us. So it brings all of this together and resembles nature. Another thing, if you come back in one year and look at this walk, it's going to look totally different. They get all kinds of stains on the walk, oak trees give you acorns, hickory trees give you hickories and those stain the walkways. Even the leaves cause staining of walkways. So all of this will take on a much more natural look, it'll look exactly like all the tree trunks that you see in this garden. That's important, Jim wants this to be natural and really bring nature together. If one looks at all the walks that weave through the property, this is just a curvilinear walk that is flowing, it's like a thread that just weaves in and out, and takes the visitor through all these wonderful views of the plants. This surface is rough, one doesn't doesn't slide down, and the water drains off. On a walkway one must make sure that it isn't lower on the upper side or it'll catch all the water coming down. You want the water to come down a hill and just slope right across, keep the water moving across the walkway, don't let it catch on one side and dig out deeper, and deeper, and deeper. You've got to make sure the water flows down, that it flows across, and then down again and across and down again. It feels cushioned, when you walk on it, it's not a hard surface, it feels like it's giving way, which it does. It actually is like a cushioned walkway. This is a great walkway, Chipseal, Joe McCrary with MDI did this walkway. He did a great job and it's perfect, it works out great. Eric agrees Jim had mentioned just how natural it feels compared to asphalt or concrete, Jim's exactly right this basically mimics the color in these beautiful white oaks and hickories, it's almost the exact same kind of bright white, gray color. Also the advantages of having it age in time is big. These pathways look like they belong, they look like they've always been here. It becomes just a natural feature of the garden. There's the practical component of being the way that people travel through the garden but importantly those practical things can also be beautiful. And these pathways certainly are.
Eric would like to discuss one more item before we leave today and that is PLANTING ON A VERTICAL SLOPE. Especially where we have significant elevation changes. We don't want to just go in and plop our plants into the ground, we need to think about how is that plant going to be best presented, particularly where we have a significant elevation change. And of course, this was something that Jim had to definitely keep in mind as that's really what this site is. Jim agrees with the steeper slopes here one must think about the plants that grow vertically and the plants that grow horizontally. If you have a vertical plant you want to be sure that when you plant on a steep slope, you dig back into the slope, then take that soil and use it in the front of the plant when planted. You've got to create a level surface when you plant the plant so it remains vertical because that was the way it was grown. If it is a plant like a juniper, or a cephalotaxus, or a dwarf hemlock, something like that, they spread out, and they're going to grow prostrate so you can dig a hole and actually plant them on the angle of the slope. But, it's real important, and it takes more soil, to plant vertically. For example, the plant behind Eric is a cut leaf dwarf dissecta maple. It had a very large ball of earth. So they dug out from behind, trying to create a level area to plant, but there wasn't enough soil to do that. So they had to bring in more soil to get that surface level so when the plant was planted, it would look natural. Then it sloped around and they had to put more soil in to blend into the steeper hillside. But it's real important to think about the slope and trying to make it natural.
Jim had a client once that called him to come out to her property, she wanted him to help her, he walked in and was in shock when he saw her slope. She had started planting plants. He thought, I've got to be tactful here, but this lady's planting all these plants improperly. She had vertical plants stuck into the side of the hillside and they were sticking out at an angle but they were supposed to grow vertically. The horizontal plants at the site looked natural, but the vertical plants have to be planted vertically. The horizontals have to spread out on the slope. When they finished she loved it, could not believe what a difference it made. So some people make a mistake on a slope, and they put the verticals in at an angle, they don't look natural on an angle. Now in 20 years, the plant would finally grow out and start growing up to the sun. But then you would have all these plants that are sticking out and curving back up to the sun and that doesn't look natural either. If you had one plant like that, it would be okay, but if you had 200 varieties of dwarf conifers you want the vertical scale, that, of course, is what he's looking for. As an example, Jim points out a dissecta maple that came from Rare Tree Nursery and Brent Markus near Portland Oregon. Brent has a great selection of rare trees and lots of dwarf conifers. He provided all the dwarf conifers for the garden. That tree had a huge ball of earth on it. They had to dig so much into the hillside that Jim had to have the men bring in more soil to get it to slope back into the bank. But when you looking at those plants they still look natural because they're planted properly. But you've got to think about the plant material, if it's a vertical plant you've got to plant vertically. If it's horizontal or prostrate, you can plant it that way. So, something important to think about when planting on a hillside.
Eric once again thanks Jim for sharing his wisdom with us. It's been an amazing day. We certainly learned a lot. And Jim thanks Eric and GardenSMART for visiting once again it was great to see you again.
We return next episode to Gibbs Gardens to take a close look at the plants that make this garden so unique. Be sure to tune in and be sure to keep following our series from Gibbs Gardens on our website.
By Dan Heims, President, Terra Nova Nurseries, Inc.
Photographs courtesy of Terra Nova Nurseries, Inc.
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