Woody Plants | Deborah Silver & Co.

Do It Now

I usually write about hydrangeas in the late summer, when they are gracing most every garden in my zone with their armloads of marvelously frothy flowers. Ha. Hopefully that written description sounds just as extravagant as they appear in full bloom. This shrub, and all of its many iterations and cultivars, energizes and endows our late season landscape with an unparalleled and succinct representation of summer. Who doesn’t swoon over hydrangeas in bloom? I do. Each properly placed and well grown shrub is covered in flowers for weeks at summer’s end. It is indeed the super nova stage of the summer landscape. A brass band playing loudly in perfectly brassy unison, if you will. Hydrangeas representing in all their glory define what it means to be robust. They are so willing, and eminently worth cultivating. They give so much more than they need or demand. They are not wall flowers, or delicate ephemerals, or gracefully weedy perennials-nor are they on that tough to grow list. They are like a freight train pulling in to the station with steam billowing up from the tracks and a horn blaring. Are you ready? If the leaf buds have broken dormancy and are swollen all along the stems of the shrubs – and if those swelling buds are greening up – it is time to prune.

Let me get what not to do out of the way first. My opinion on the matter is all I have to offer. Do not prune in the fall. Pruning is a call to grow. Encouraging a shrub that is facing the winter to get up and grow is just not a good idea. Your best move is to encourage the long sleep. Movement towards winter dormancy in woody plants starts in my zone in August. Once the leaves turn color, mature, and drop, leave all of the rest of the shrub intact. The most important thing to do to hydrangeas in the fall is nothing. Do not cut the flower heads off. They look lovely with snow on them, and they wave in the winter winds. That cinnamon brown color is beautiful with evergreens. If you must remove the flower heads, OK, but do not cut these shrubs down to the ground in the fall. That will force them to sprout from below ground in the spring. Be merciful. Leave at least 3 or 4 buds above ground when you prune-in the spring. If you are growing big leaf hydrangeas-as in hydrangeas that bloom on the previous year’s wood/growth, do not prune in the fall or the spring. Prune them promptly and only after they finish blooming. If you don’t know which type of hydrangeas you are growing, find out before you prune.

Hydrangeas do not respond very well to a formal shearing. Few plants do. Shearing hydrangeas encourages multiple breaks below the cut, which result in a dense thicket of stems and leaves at the top. The bottom half of the shrub gets shaded. I am amazed at how many hydrangeas I see pruned like this, but it is not good for the health of the plant, or the flowers. I give my hydrangeas a shag haircut, keeping the stems at the top shorter and the stems nearer the bottom longer. The idea is to provide a sunny and airy space for each branch to live free. You can see this arrangement in the location of the flower heads in the photo above. Each branch has its own address.

What might not be so obvious is that these last 2 pictures show two different types in hydrangeas. On the far left and far right of a center block of Limelight hydrangeas, as in Hydrangea paniculata “Limelight”, are rows of Incrediballs – Hydrangea arborescens “Incrediball. They add flowers at a lower level, and they bloom earlier than Limelight. Their upright plant habit and carriage is vastly superior to their predecessor, the storied “Annabelle”. You can see the Incrediball flowers are fairly round, and the Limelights are broadly cone shaped. A certain amount of legginess is inevitable with Limelight. That mess of twigs is what you get over the winter with them. The Incrediballs help cover up those bare legs. These cultivars have different parentage, but they are pruned the same way. They bloom on new growth. On what will be the current years growth.

So if it’s not appropriate to prune hydrangeas by shearing, what is the purpose of setting stakes and string? My yard, where these photographs were taken, slopes dramatically from one end to the other. The blocks of hydrangeas are a good distance apart. I would want those blocks to loosely resemble one another. The only way to tell if they approximately occupy the same spot in the landscape composition on both the north and south is to set up a level line. It’s easy to do with a bamboo stake or metal fence post, and a ball of spring. A tiny level can be clipped on to the string.

Pruning by eye can be incredibly inaccurate. I see a lot of that too. Pruning that matches uneven terrain, or follows a sloping driveway. Or pruning just to prune, with no thought to the horizon. I see that too. Sometimes it is hard to believe a level attached to a string line is accurate, but it is. I would never trust my eye to see a level line for pruning. It is terrible to wade through a big pruning project only to discover your vision for them is lopsided. And what is required to set it to right is not possible until the mistake grows out. I shudder to think of that. Happily most plants are very tolerant of off the cuff pruning. The recovery just takes time.

My level line set up is an approximation of the horizon. In the ballpark, as it were, or within shouting distance. It is not exact. It does not represent or enforce a rule. Nor does it rule the pruning process. It provides orientation. As in up and down, and left and right. It provides a framework from which to work. Taking the time to set up 2 poles and a level line is a way to walk away from the the noise of the day, and study on this first foray into the new garden season. It is a way to get ready for the job at hand. But in spite of all this, should you decide to prune your hydrangeas from the hip, Mother Nature will treat you just the same as any other gardener. Indifferently. But indeed you will notice the difference.

The pruning of my hydrangeas is underway.

Posted on: March 28, 2025 18 Comments

Filed Under: Woody Plants, garden maintenance, flowers, the garden, Seasonal Tagged With: pruning hydrangeas, Hydrangea Limelight, hydrangeas, pruning woody shrubs, hydrangea Incrediball

The 2020 Hydrangeas

The hydrangeas in bloom this year have been beyond gorgeous. I have never seen them better, and I have been growing hydrangeas for a long time. The object of my affection and admiration are white flowering varieties that bloom on new wood. Blue and pink hydrangeas that bloom on old wood – this would be the bigleaf hydrangeas, or hydrangea macrophylla – are not truly bud hardy in my zone. Unless they have a mild winter, whilst mulched from the soil level to the tops of the branches, the flowering will be sporadic and disappointing. If yours bloom profusely and reliably in Michigan, then count your blessings. The whole point of hydrangeas in bloom is the sheer splendor that comes from abundance. A happy hydrangea is so loaded with blooms the slender stems of the shrub will bend over from the sheer weight and volume of them. If you must have blue hydrangeas in all of their splendor, then pack your bags for Nantucket, and read no further. The Bobo hydrangeas pictured above have astonishingly good care. The entire bed is on drip irrigation – essential when hydrangeas are in full sun – and that irrigation is monitored and updated frequently. I am quite sure they are fertilizing in late winter/early spring. Some apply Hollytone, by Espoma, or a slow release balanced fertilizer. The reward is an ocean’s worth of greenish white flowers.

That is not all. Later in the season those blooms will turn towards pink, and then rose pink. The fall display is every bit as beautiful as that in late summer. Add the yellow fall color on the leaves, and you have a visual treat that is quite spectacular. A good shrub provides interest in the garden over a long period of time. Hydrangeas are particularly generous with a long period of bloom. I leave the flower heads intact over the winter – why not? That cinnamon brown color is strikingly beautiful. Of course there will be those blooms that break off and blow around, but that cleanup is manageable.

This hedge of Limelight hydrangeas was planted for a client at their restaurant many years ago. I want to say at least 10 years ago, probably more. I am quite sure that they get watered; my clients takes great care of all of their plants.The soil is that typical Oakland County Michigan airless and non-draining clay-we planted them well above grade for exactly that reason. I have no idea what pruning and feeding care they get, but I can say their maintenance company was not permitted to work this year until May. So the spring care was fast and loose. Behind me in this picture is Woodward Avenue – a main road with 3 lanes going both north and south. It is packed with automobile traffic around the clock, in the 45-50 mph range. I would say the hedge is 25 feet off the road, and endures plenty of exhaust in the summer, and an equal amount of road salt in the winter. This commercial planting is stunning.

This hedge of Little Lime hydrangeas is relatively new-it was planted 4 years ago. The flowers are at that fresh green stage, as they are just beginning to bloom. This exposure is westerly, which is a great location for hydrangeas. They need at least 6 hours of sun a day to bloom profusely. I am astonished at how many articles I read that suggest that hydrangeas do well planted in the shade. I have seen plantings in shady areas that range from sporadically blooming to passable, but I have yet to see a hydrangea thrive in shade. Of all the hydrangeas, the oak leaf is the most shade tolerant. Tolerant is the key concept here. No flowering plants, with a few exceptions, love shady conditions. They tolerate them. Find a sunny spot for your hydrangeas. These Little Limes get occasional supplemental water.

I get no end of questions about spacing. I have seen spacing recommended anywhere from 3′ to 8′. This hedge was spaced at 3 feet on center, with 2 rows of plants in staggered positions. The bed is 9′ in depth, and the Little Limes have filled that right up. An 8′ spacing on a Limelight hedge will produce a series of shaggy ball shapes. A closer spacing will produce a more uniform look to the hedge. I think spacing is primarily a matter of personal taste. If you are willing to wait a few years for a group of hydrangeas to grow together, then space them out. If you are after a densely growing hedge then space them closer. If there is a specific space to fill, then space to fit that particular space. Do I think one spacing is superior and produces more healthy plants than another – sun and water being comparable – ? No.

I have 2 blocks of Limelights at home that have been in the ground for close to 20 years. They were spaced at 30″. They have been healthy and heavy blooming every year. I have had Japanese beetle damage to the leaves, and scorch when I didn’t water enough, but they perform the same as a group spaced at 4 feet apart. I can vary the style and extent of my pruning every year, and not be able to see any difference in the blooming plants. A good friend has planted and maintained miles of blocks of Limelights in the median on a major north/south road in my area. They are the best blooming hydrangeas I have ever seen, in a year of great blooming hydrangeas. I asked her about the care. They routinely feed with Hollytone, and they do water. The only difference this year was that they did not prune as hard as usual. Do I think this made the difference in the performance? Maybe, or maybe not. Do I think the weather conditions were perfect? Our season has been very hot and dry. Would I expect this to be great for hydrangeas? Not really.

Hydrangeas will tell you when they need water. Those big thin leaves clinging to the stems-as in the above picture of a hydrangea on standard – is a clear SOS. I do err on the side of water generosity, as I believe that plants stressed from being too dry perform at a less than optimal level. Newly planted hydrangeas need very careful monitoring for water. They grow so fast that most potted plants available for sale are root bound. If that root ball goes dry soon after planting, it is of no consequence how wet the soil is a foot away. The hose needs to be aimed directly at the crown of the plant.

This is all by way of saying that insofar as gardening with hydrangeas is concerned, various approaches to their cultivation can produce healthy and beautiful plants. They are so versatile in the landscape, as this pair of pots planted with Limelights can attest. Most and best of all, they are forgiving of neglect, and respond strongly to attention and care.

I have been enjoying them for weeks now.

Posted on: September 9, 2020 50 Comments

Filed Under: Woody Plants, Summer Tagged With: Hydrangea Limelight, hydrangea paniculata, Limelight hydrangeas, Little Lime hydrangeas, panicle hydrangeas

Part 2: The Landscape To Go With

My last post dealt in detail with the process of relocating a driveway for my clients. It was a huge investment both in resources and time-from early spring until late summer. Good for me that my clients are incredibly patient people. The property features lots of trees of considerable age. There was no interest on anyone’s part to change that. The landscape would be concentrated near the house and new drive court. The open area once occupied by the old driveway would be a sweeping arc of grass similar in shape to the arc of the driveway – but larger. That grass arc would be punctuated by a few strategically placed specimen trees. Those new trees would have plenty of space to grow to their mature size.

The drive court is of considerable size too. The house is a long way from the road. Though the climb up is at a much easier angle than before, it is still a climb. So a drive court that could accommodate visitors coming and going was of paramount importance to my clients. On the plus side, it makes an admirable makeshift basketball court, and it is easy to park out of the way of the garage doors. The landscape embracing the drive court circumscribes it in a large radius, the size of which was dictated by a pair of retaining walls installed in tandem with the driveway. I can safely say that the only flat space on this property exists inside the walls of the house. All other flat and navigable space had to be created.

I was interested that the landscape have a strong, simple, and largely evergreen accompaniment. The formal nature of it accomplishes two things. It is in striking contrast to the natural landscape which surrounds it. And it would be fairly simple to maintain. Blocks of buxus “Green Gem” in alternating sizes would need a routine and accurately timed source of water, and a yearly pruning. Planting these 9′ by 9′ square blocks in an arc created plenty of suspense for those of us who installed it. There was a lot of site work determining just the right plant placement. It has unexpectedly proved to be the ideal nesting spot for a turkey. Green Gem is very hardy in my zone, and it tolerates very cold and windy winters. On the top of the hill, hale and hardy was an important criteria for plant selection.

At the same time, project manager and driveway builder Ralph Plummer, owner and operator of GP Enterprises, was hard at work doing what he loves the best. The placement and planting of large specimen trees. If you need big trees, there is no better source. I feel sure that there are countless landscape contractors in my area who use his services. He has the resources, equipment, and experience to place large material in the landscape. As so many of the existing trees were of considerable size, large trees were called for. Though the London Planes he planted for me on this project were 25′-30′ tall, they are still dwarfed by the older trees existing on the property. London Planes are one of the largest shade trees native to North America, and these three will have plenty of room to grow. There is a thought to the future too. Trees, like any other living thing, have a life span. They would be the beginning of the next generation.

A Norway spruce of comparable size was planted in addition to the plane trees. The large lawn area would have all the dressing up it would need. Watering new trees in a lawn area is not so simple. Irrigation meant to water a lawn does not provide the deep soaking required by large trees of recent transplant. A drip irrigation zone for the sole purpose of keeping these new trees adequately watered was installed. The lawn irrigation zones do not overlap and water the trees. This takes careful planning and installation-just the kind of thing for which Ian Edmunds Irrigation is well known.

Of course I was imagining what the property would look like with grass. But we were a good ways away from that moment, at this moment.

The big trees did provide some privacy to the house on the hill. I took this picture from my car, driving by.

The blocks of boxwood feature Venus dogwoods. Those trees will provide better and better leafy contrast and size to the boxwood as they grow. They like a fair amount of sun, and are hardier than either of their primary parent trees – the Kousa dogwood, and the pacific coast species cornus nuttallii. When happy, they will put on a foot of growth per year.

The retaining wall created a substantial planting space on the house side of the driveway. We were happy for the good soil and easy planting conditions. Per the plan, the house side of the drive court repeated the boxwood and dogwood pattern of the opposing side, but added several other elements. A columnar spruce, picea cupressina, will grow every bit of 25 feet tall, with a mature width of but 6 feet. It will give the chimney a run for its money. This is a large house without so much available planting space. A strong vertical plant will help the landscape keep up.

That spruce is surrounded with a mass planting of the dwarf red barberry. That dark wine red color is very friendly to the color of the brick on the house.

This small area between the front porch and the person door in to the garage was a high visibility spot that lacked any appealing features.

Once it was determined that the only traffic to this door was from the driveway, the new landscape was installed accordingly. The window in this picture is one of the few that look out on to the landscape. That view out is better now.

It was always intended that the retaining walls installed in support of the landscape would be softened by a double row of Limelight hydrangeas. The white flowers on the mature shrubs would provide a stunning backdrop to the boxwood on the upper level drive court. A change of level provides great interest to any landscape, large or small. The fact that they will describe the entire upper arc of landscape means they will read strongly from the road. All of the big trees had generously sized edger strip installed around them. No need for a mower to brush up against them, or a lawn trimming tool to damage the bark. Of just as much visual importance here is the shape and sweep of the grass to come.

By the time that we were able to complete the front yard landscape with plantings at the road, it was very late in the year. A group of white pines that my clients had planted on their property had spent the summer heeled in to protect them. They were moved to a pair of large beds at the driveway entrance off the street. A number of additional white pines were added to the original group, and all of the trees were under planted with the spreading juniper, “Calgary Carpet”. I am not a huge fan of junipers, but this one has a beautiful horizontal habit, and a lovely sheen to the branches. Culturally, they would be a perfect companion to the white pines.

It was December when we finally got to mulching all of the plantings. It was the least we could do, given that a rainy late fall meant the grass would have to wait until the spring.

A pair of pots were selected for the front door, and arrangements for the holiday and winter season were installed.

Early this April we were able to sod all of those bare dirt areas. What a relief.

A few months later, the sod has knitted and rooted in. There is no sign of all of the work that went on most of the previous year. All of the large trees seem remarkably good, considering they were transplanted less than a year ago.

The curving beds of Limelight hydrangeas will be blooming soon.

The landscape near the house is thriving.

The entrance beds are taking hold. All of the white pines survived their first winter in this spot with little damage. As for the tire tracks on the grass, I stand by the design of how the drive meets the road. I am sure the damage is from the latest set of trucks and equipment.

Under construction now, the back yard. What you see here is a temporary stone access road. More on this later.

Posted on: July 20, 2020 19 Comments

Filed Under: Hard Surfaces and Structures, Landscape Design, Woody Plants, Deborah Silver and Co Inc Tagged With: white pine, juniper "Calgary Carpet", limelight hydrangea, landscape renovation, buxus Green Gem, GP Enterprises, Ian Edmunds Irrigation

Sheared: Part Two

Anyone who chooses to look up topiary plants of distinction on their computer will find no end of articles with pictures of grand gardens featuring breathtaking topiary plants. Many of them have been cultivated long enough to have acquired shrine status. The size and scale of many of these topiary plants is staggering, never mind the work that is involved in keeping them up. I enjoy seeing them as much as the next person. But I also have great admiration for gardeners who on a more personal scale grow on plants that require a substantial and steady commitment to the maintenance. The single ball boxwood topiaries that are pictured above began as fairly modest plants grown at a farm specializing in boxwood in the Pacific Northwest. My memory is of a head diameter of perhaps 10 or 12 inches. The trunk would have been in the neighborhood of a quarter to a one half inch caliper. When these topiaries arrived, their trunks were secured to bamboo stakes virtually identical in size to the trunk, and as tall as the the stem and head. This is smart staking. The head of a topiary is the most vulnerable to catching the wind, and snapping off. Young topiaries are fragile. If you expect to grow them on, protect every part of them, bottom to the very top. I can’t say exactly how long we wintered these trees for my client, but it may have been 8 years or so. They summered in pots, and wintered in our unheated garage space. We were taking no chances with winter weather. Did we do the yearly pruning? No. We farmed that job out to an expert.

These topiary starts of lemon cypress- cupressus macrocarpa Goldcrest “Wilma” will top out at 3 feet or so. Outdoors, in a zone 7 or warmer, Goldcrest can grow to 16′ tall or so. The dwarf version Wilma makes a good house plants, provided they have a really sunny south facing location for at least 4 hours a day over the winter. They like cool temperatures, so wintering them over in a house kept at 72 degrees can be a tough go. Like most cypress, they appreciate evenly moist soil. If you let the rootball dry out, you have lost the plant. It is the juvenile foliage that has the best lime green color, so regular trimming will preserve that color. They appreciate a summer outdoors, but I try for a full sun morning with a little protection from the worst of the afternoon sun. Be advised that each stem you trim will probably turn brown at the cut. But once that branch starts growing again, that cut mark will fade from view. This is a quick look at the care issues with lemon cypress. Should you have the idea to grow them, look up their culture on line, and read.

No topiary in our zone is more challenging to grow than a myrtle. Myrtis communis compacta is an evergreen shrub that is especially genial and tolerant of frequent pruning. What they are not tolerant of is dry soil. During the winter, they need bright light, and even moisture. Myrtle topiaries of the scale and size pictured above requires a passionate and faithful grower. I have not seen myrtle topiaries of this size and scale very often, but I can attest that these clients lavished no end of attention on them.

Certain trees are quite tolerant of close pruning. The carpinus pictured above has been expertly trimmed by a virtuoso with shears. I am quite sure there was a lift involved. They respond enthusiastically to pruning. This sheared shape is close to the natural shape of the tree, meaning the health of the tree is not endangered. A tree is a vast subject for a topiary, but the time between prunings can be fairly long. Linden trees are equally amicable about this kind of pruning. The boxed lindens on the driveway at Detroit Garden Works are pruned every other year at most.

Limelight hydrangeas make gorgeous single ball topiary plants. The loosely spherical head in full flower is quite spectacular. As hydrangeas are naturally very coarse growing plants, their shape is a study in contradictions. They are informally formal. Our grower trims the hydrangea standards twice a season. Once in late March or early April, and again later in May. This schedule helps to produce a strong network of branches that helps keep the flower heads aloft. Even so, we often tie up the branches with stretch tie, to make sure the framework is strong. The stake is as tall as the very top of the plant.

Italian cypress is not hardy in our zone-how I regret that. But if a client is willing to winter them over in an unheated greenhouse they can provide a dramatic focal point to a container for a number of years. This evergreen is naturally very narrow and conical, so the pruning required to keep them tight is a matter of emphasizing and more clearly defining what is already there.

This young boxwood topiary is delightfully under scaled for its under planting. The boxwood head has not been sheared, but left to its natural devices. It gives a very traditional landscape form a much more contemporary look.

Yews make good topiary subjects, although they do not respond as well to close shearing. This double ball taxus lived for 4 years in this pot, all year round, before succumbing to a particularly cold winter. A little looser treatment produces a better looking plant. As in green through and through. Drastically sheared yews are common in the landscape, but the development of a topiary form is not a goal. It is a once a year effort to exert control over a plant that may be poorly sited. Improperly sheared yews sporting a thin skin of green, and bare branches and trunks underneath is not a good look. It also contributes to the decline and ill-health of the plant. Junipers are rough coated evergreens, but they respond surprisingly well to pruning. They are also happy with a long term home in a large container. They are low maintenance shrubs and trees in general, so they shrug off the shearing.

Westringia fructicosa, commonly known as Victorian rosemary, is a dwarf shrub that responds well to development as a topiary. I rarely see it offered for sale, which is unfortunate. This particular single ball topiary made a beautiful container specimen.

Culinary rosemary, or salvia rosemarinus, is a well known subject for topiary. The clippings smell delicious, and its use as an herb is legendary. This particular unsheared topiary is underplanted with fiber optic grass and strawberries.