My idea of sheetcake has nothing to do with cooking batter in a pan. It has everything to do with the idea of planting shrubs in masses. There are those times and places where planting out in rows has its place. Field rows of corn, asparagus, peonies or cutting flowers can be an astonishing sight. Many years ago I designed just such a garden for a client who tithed the use of the land surrounding his house to his church. This, the intersection of agriculture and landscape. Some years later I dicovered the work of the Spanish landscape architect, Fernando Caruncho. His gardens explore the idea of agrarian based landscape design on a grand scale. His landscape, Mas De Les Voltes, I admire as much as any landscape I have ever seen. But my intent with the above pictured landscape was to suggest that a drivecourt had been carved out of a mass of taxus. Though most of the mass is actually drivecourt, the suggestion of great mass remains. Shrubs planted formally en mass-I call this a sheetcake.
Caruncho had designed a garden in Madrid, La Florida, in which four giant rectangles of escallonia macrantha have been formally pruned into flat “tables” twenty inches high. I have never forgotten this gesture. There is another way to conceptualize this; the shrub is actually a a very tall groundcover. Describing the effect of such a planting as a sheetcake enables anyone to visualize exactly what it looks like. The now large English oaks set in squares of pachysandra rain leaves onto the yew sheetcakes in the fall. Weather working on the landscape provides something new to look at almost every day.
Very small urban properties can be sheetcaked to good success. One has to choose as few gestures from many possibilities, given a small space. Too much going on in a small space dilutes the impact of the landscape. In this case saying less truly is more.
A very flat piece of land achieves a change of level with the interaction of two plant materials of different heights.
The dusting of fall leaves provides another dimension as the limelights are fading.
A sheetcake garden is an effective way to showcase abrupt changes in grade. I am all for celebrating any unusual characteristic of the land. One client had a low lying front yard, and an active artesian spring. I dug the ground deeper, and created a pond. The sidewalk to the front door was actually a boardwalk over the pond; you get the idea. The artesian spring was treated as an asset, rather than a nuisance. Accommodating nature helps produce a successful project.
A tree inset into a sheetcake provides another layer of interest. I have talked about the spent magnolia petals on these boxwood in the spring-it is a sight for my gardening eyes.
A sheetcake garden; it sounds good, doesn’t it?
Topiary is the art of pruning, and training a plant to grow in whatever shape you might fancy. Plenty of plant species lend themselves to this kind of treatment. The above pictured lantana is seven years old. It began as a small plant, whose side branches were removed until the primary trunk was about four feet tall. A devoted grower then pinched back the main leader-the first step in the formation of the top. As I like slightly flattened spherical shapes in topiary, we keep the top pruned, and grow the side shoots wide. Lantana flowers profusely in hot weather, it makes a strikingly statuesque topiary plant. In the fall, I cut the head of the plant back by two-thirds,, strip all the remaining leaves off, and stash it in the greenhouse. I strip the leaves off, as lantana is a magnet for whitefly-and they multiply like lightening in a green house environment. What they require is plenty of trouble, but it is glorious in form and flower. 
Well grown large topiary plants are expensive. It takes a lot of time to grow them on-sometimes years go by before a plant can be sold. This dwarf variegated euonymus with a batch of leaves atop a stem tells the story. In ten years, this plant will not be much taller-just much stockier, with a full head of leafy branches. As euonymus is a hardy shrub, they like to be wintered in a cool light place. 
Bay Laurel is not hardy here, unfortunately-so a greenhouse is a necessity in the winter. This plant is 14 years old. This single ball topiary suckered at the base so persistently, I finally just let it grow. The formal shape is easy to keep up; you can see it needs a little haircut right now. There are many kinds of topiary shears available-I like short bladed snips, so I can cut branches without slicing into the leaves. Any leaf that is cut will show that telltale browing on that cut edge within days. �
Ivy can be readily be trained over a wire form. This makes it an ideal subject for fast growing. The vines are tied to the form to provide completely coverage, and the vines are clipped as needed. Hedera algeriensis ” Gloire de Marengo”, or variegated Algerian ivy, has large glossy leaves, and a prominent white variegation; old topiaries grown from this plant are striking. A bonus-it is possible to winter ivy topiaries over in the house. 
The coleus topiary I let go after two seasons-they seem to loose vigor. The minute you decide to grow a plant in any form which is not its natural form, there will be maintenance problems down the road. Plants tolerate being fooled with by people-they rarely love it. Plants that naturally lend themselves to this treatment are easier to look after.
On my top ten list of frequently asked questions, the culture of evergreens in pots ranks right up there. In theory it sounds great. You invest in an evergreen which will provide you with a center of interest that looks great no matter the season. Perhaps there will be room on the edges for a few seasonal annuals. The work and expense up front is considerably more than planting smaller and less expensive plants, but then you are done. Redoing one’s pots with new plants every new season no doubt is a lot of work and expense. But as with everything connected to growing a garden, one is rarely “done”. The Italian cypress in the pot pictured above is not hardy in Michigan, nor can one leave a terra cotta pot such as this one outdoors during the winter. The cypress has to be wintered in a greenhouse cold storage area, and replanted every spring. The pot is put away. There is time and trouble hauling it back to the greenhouse in late fall.
This 25 year old rosemary has spent 25 winters in a glass house. It is an evergreen-should you live in Greece or Italy, or California. Michigan winters are fiercely cold. However unfair it seems, rosemary is just not hardy here. In return for the extraordinary pleasure of owning an old rosemary such as this one, my client is willing to weather what it takes to keep it alive and healthy.
Mugho pines, both the shrubby and the topiary forms, have the reputation of good survivability in pots. Critical to that survival is proper watering. Should you quit watering this evergreen when your geraniums go down from frost, you are almost certain to loose it. Judicious watering right up until the soil ball is frozen solid is a must. If this evergreen were to unfreeze in a January thaw, a watering might be in order. When the soil thaws in the spring, the watering should be resumed-even if this is long before you plant your other pots. What evergreens in containers require is not for the faint of heart.
This grand old myrtle topiary was beautifully maintained, for 11 summers. The 12th winter in the greenhouse, a furnace went out, and it froze. It has been in the greenhouse for the past two years; we are trying to coax it back to health. Owning plants like this is a big committment with little in the way of any guarantee. Just because you have provided next to perfect care for a long time does not mean you cannot loose it. Evergreens in containers are for gardeners who relish risk.
These mugho pines on standard have lived in these orangery boxes for 6 years. At some point, they should be taken out, root pruned, and reset in fresh soil. They will most certainly decline without this maintenance. No plant stays the same, just because its container stays the same. Plants will prosper and grow, or sulk and decline-one or the other.
Boxwood is a good choice for a container. As this French terra cotta pot cannot be left out, I wheel this entire assembly into the garage for the winter. This species, Buxus Microphylla, is very tough; my hedge on the southside of my building never winter burns. In the same spirit, it tolerates a mostly dark and unheated garage from November until March. At the first sign of moderating temperatures, I take it back outside. A garage can get too warm for holding plants dormant long before the outside temperatures moderate.
Waxleaf privets are an aristocratic cousin of our hardy privet. The large leaves are lustrous and juicy looking. They are hardy in zone 7, so they can be wintered in an indoor spot without much in the way of heat. They grow slowly, and are available in big sizes; there is demand for the topiary forms from gardeners in more temperate regions. They take well to pruning and shaping.
Luckily glass reflects light during the day. Her life would not be on visual review from all the neighboring properties-except at night. Given the very small size of the lot, the architect had designed a basement garage accessible from a sharply pitched drive. I did admire how he managed to exclude the garage from the visual presentation of the of the house. The garage is rarely the most beautiful feature of a home. It was necessary to retain the soil surrounding the house in order to permit a drive surface below grade. This was accomplished cleanly with corrugated steel capped in corten.
The house is very tall, and the stone and glass edifice is starkly contemporary. The land unoccupied by the house amounted to an L-shaped strip barely wider than the right of way between the street and the sidewalk. Some homes are architecturally demanding buildings. By this I mean their sculptural element dominates the space. My client has a big love for contemporary art and architecture-such that the prospect of living in a sculpture appealed to her. It was my job to design a landscape that would in no way interfere with the one thought-the sculpture that would also provide a home to her. This landscape would in no way be about plants; it needed to be about sculpture too.
The slanted steel roof presented its own problem-how to handle rain water. A drainage system was designed, and approved by the city. It was very expensive, but it prevented water from flooding the neighboring property. The front porch under construction here would necessitate a big flight of steps, as the bottom of the glass panels matched the grade of the first floor living space. 
As with any contemporary landscape, a restricted palette of materials makes for a clean and strong statement. I planted a slew of Salix purpurea nana-commonly known as dwarf actic willow. Its gracefully meadow-like appearance sharply contrasted to the hard surfaces of the house, and softened them. The blocks of willows would be mulched in granite gravel. The columnar poplars would not obstruct the views of the house, but would slightly break up the stone and glass surface. The placement was dictated in part to provide good views from the inside of the trees outdoors. 
The transition from the willows to the walk would be handled by lawn. It was important for a house this size to visually include the right of way landscape, so more lawn was in order. 
Given some time, the willows took hold. Their dense billowing appearance is simple and handsome. These densely twiggy shrubs are solid and graceful. Their mature height barely sweeps the bottom of the glass panels. Their slightly bluish cast repeated the blue-green color of the poplar leaves.
The walkway to the side door is embedded in this meadow as well. A retaining wall which permitted windows to be installed at the basement level is no longer visible-as the wall is strictly utilitarian, we screened it from view. The look of a shrubby willow reminds me of an ornamental grass. Ornamental grasses are difficult in the winter season. Leave them tall over the winter-heavy snow will knock them over, and spring winds will scatter their broken branches everywhere. Trimmed to the ground in the fall-that look is not so appealing either. Some prominent places in a landscape wanting grasses might benefit from being shrubbed up with dwarf willows. 