Thursday, April 13th, 2017 at 7:00 am
When I started my education in horticulture, I requested a space in my mother’s vegetable garden. She generously let me use a 3 by 10 ft area in the shadiest part of the garden, alongside the neighbor’s Arborvitae hedge for my mad scientist experiments in gardening. Over the course of several years I accumulated and lost a variety of plants, but the Bergenia always lasted.
Bergenia cordifolia or Heartleaf Bergenia is an herbaceous perennial with medium rounded leaves that grow in a rosette up to 1.5 feet tall. The glossy leathery leaves offer a different texture in the landscape that contrasts well with the finer textures of grasses such as Carex or Hakonechloa. In spring, Bergenia puts up 1 to 1.5 foot stalks of clustered pink to red bell-shaped flowers. In late fall to winter, the leathery leaves usually turn wine red and can be left until spring. Bergenia does best in part shade with moist, humus-rich soil.
In spite of its preference for part shade, Bergenia does an excellent job enduring full sun and fully shaded locations as well as dry or wet. While it may not tolerate very wet shade or very dry sun, it adapts well to most other sites. Bergenia even does well under pine and spruce!
Bergenia is also a great plant for a garden that kids play in. The flowers don’t attract much in the way of pollinators. Though the occasional bee or butterfly may visit, they’re far and few between. Bergenia is also tolerant to some trampling as well as to salt, deer and rabbits. Best of all, they’re interactive. Take a leaf and rub it between your thumb and forefinger to hear the leaf squeak. This is the reason for its common name: Pigsqueak.
If you haven’t tried Bergenia, I invite you to try planting a small mass of Bergenia cordifolia or Bergenia cordifolia ‘Winter Glow’ in a shady area of a yard. The leathery leaves offer evergreen, virtually maintenance free coverage throughout the year and the pink bell shaped flowers will help brighten up the spring for both kids and adults.
Monday, April 3rd, 2017 at 7:00 am
While the word “willow” may conjure a specific image in your mind, the willow genus, Salix, is very diverse in nature, representing a variety of trees and shrubs that span the globe, primarily in temperate and cold climates of the northern hemisphere. They thrive primarily in moist to wet areas in sun to shade and have been used by humans for centuries. When you take a closer look at willows, it’s easy to see why we value these plants.
When we look at what Salix do for our wallets, an initial investment could range anywhere from a free plant (or cutting) to a several hundred dollar tree. All of this depends on initial tree size and variety, but long term savings can easily amount to thousands of dollars over several decades based on placement. As most willows tend to have a medium to fast growth rate, the savings from shade and wind protection will become obvious within a short number of years. This is one reason why shrub willows make an excellent choice for screening and windbreaks – they grow very quickly which can save on heating or otherwise prevent damage to more sensitive (or expensive) plants. As they’ll also cut down on noise it may also save you money on aspirin.
While I’m kind of kidding about saving money on pain killers, willows do contain salicylic acid, which is a precursor to aspirin. Willow bark has actually been used as a natural painkiller for millennia. Salicylic acid is also used as an acne treatment, though I recommend against just rubbing your face against willow trees.
Willows can also be coppiced or pollarded and will readily resprout. While this is now sometimes done for aesthetic reasons, this kind of extreme pruning was often done (and sometimes still is) for firewood as well as making furniture, homes, wattle fences, toys, tools, and more. Willows are perhaps the most forgiving to this kind of treatment due to their rapid growth rate. If you’re regularly doing this kind of extreme pruning, it is wise to also fertilize as this will eventually deplete soil nutrients.
Willows offer a lot to the wild things of the world. Caterpillars in particular love this plant, though you might not know by looking. Willows support over 400 types of caterpillar including the viceroy and red spotted purple. The caterpillars that feed on the leaves of willows are incredibly valuable to many birds species such as chickadees, grosbeaks, nuthatches, orioles, warblers and woodpeckers. These soft bodies caterpillars act as an important food source to baby birds that cannot yet digest seeds. These trees and shrubs also offer nesting opportunities for those same birds. It’s not just the birds, but also the bees that benefit. When other nectar sources are not readily available, many bees take advantage of the pollen and nectar on willow catkins to sustain themselves.
One of the most fascinating things about plants in the genus Salix is that they can be so easy to propagate! If you ever have access to a willow in spring, try cutting some branches, about a foot long and of pencil thickness, and place them a few inches deep into a pot full of soil. Keep the soil moist and within a few weeks you will likely see growth. While some species don’t set roots very well, most will root quite enthusiastically. This can usually be done in a vase as well. This is a fun experiment to do with kids. Try changing up some of the variables like amount of light or size of the branches and see what happens!
Growing up the child of Polish immigrants, every Easter was full of both Polish and American traditions. The one I recall most vividly was when my mother would go out to collect pussy willow branches from the tree outside. While she typically just used them for decoration or had them blessed the Saturday before the Easter Holiday, it is a tradition in many Slavic countries to have them blessed beside (or instead of) palms the Sunday before. Willow branches can be considered a metaphor for Easter – the flowers erupt from the seemingly dry branches. It’s a symbol of resurrection and the start of spring.
The fuzzy catkins of Salix discolor.
Fundamentally, willows are great plants, especially for wet spots. They are useful in crafting and saving money. They are kind to wildlife and fun for kids. For me, the white fluffy catkins of willows remind me of home. Beyond that, there are few pleasures quite like resting under a willow on a warm spring day as the breeze flies through the branches and over the leaves.
Tuesday, March 28th, 2017 at 8:00 am
The past few months have been peculiar to say the least. The unseasonably warm January and February left many asking what happened to winter? While we felt unsure of the season, these early blooming shrubs were just waiting to pop and bring the season to life!
Hamamelis vernalis – Vernal Witchhazel
Hamamelis x intermedia – Hybrid Witchhazel
If you didn’t know, the word “vernal” comes from the latin word for spring, so it should come as no surprise that this is the time for Hamamelis vernalis to shine. Perfect for a sun to part shade with good moisture, the flowers erupt out of this plant from February to late April. The long, strappy, fragrant petals create a unique look that stands out in the garden or especially against a building. This native shrub often grow 6-10 feet tall and 8-15 feet wide. You might also consider trying some of the Hamamelis x intermedia hybrids. While not native, they have a similar look and will do well with similar conditions. Best of all, the hybrids come in a wide selection of flower colors ranging from lemon yellow to brick red. Witchhazel also has great fall color which can range from golden yellow to crimson.
The flowers of Hamamelis x intermedia ‘Moonlight’ exploded out of the plant this week and smelled delectably fragrant!
Forsythia sp. – Forsythia
It’s hard to miss these classic spring flowers in landscapes across Illinois. The bright sunshine yellow flowers make Forsythia glow from March to April (and sometimes as early as February). While flowers are typically about the size of a nickle or dime, some varieties such as Show Off have flowers as big as a quarter! The plants also have a nice display of gold to ruby fall color. Forsythia come in many sizes varying from 1 foot to 9 feet tall. For this reason, many of the larger varieties must be pruned to maintain good size and habit. Plant Forsythia in full sun to part shade with moist soil for best results. After a very harsh winter, Forsythia may not flower well, so protected spots are preferred for this impressive shrub.
The flowers of Sunrise Forsythia are about the norm but still beautiful.
The flowers of Show Off Forsythia are huge!
Cornus mas – Cornelian Cherry
Cornus officinalis – Japanese Cornelian Cherry
Cornelian cherries are the cheerleaders of spring. In March to April, pom poms of small yellow flowers pop out of the branches to greet the season with a surprising exuberance. While it may not be a show stopper like Forsythia, it’s a shining reminder that spring is here. As the bright yellow flowers fade away, glossy green leaves emerge to fill the space. Eventually in Mid to Late Summer, glossy red fruit appear beneath the leaves which are commonly eaten by birds. In fall, the plants usually have a degree of red fall color before dropping leaves for winter. Cornus mas and Cornus officinalis are very similar in appearance, but are most easily distinguished in winter by the more attractive, textural bark of C. officinalis. Both make excellent stand alone shrubs, but C. mas tends to have a tighter habit, so it makes for a better hedge. The fruit, while similar in appearance, is somewhat different in that C. mas has sour, juicier fruit and C. officinalis has more astringent fruit similar to Aronia melanocarpa. Plant these Cornus in full sun to part shade with moist soil for best results. Both grow to about 25 feet tall and 20 feet wide but can be easily pruned to maintain a desirable size.
The small yellow pom poms of Cornus officinalis.
Now that we’re a few days past the equinox, I think it’s safe to say that spring is here and while we may still have some cold days ahead, all it takes is a quick look around to see things coming to life. I hope seeing some of these shrubs will bring a little brightness to these early cloudy days of spring.
Monday, March 20th, 2017 at 1:00 pm
Last week I focused on 4 native herbaceous perennials that are great for the conventional landscape. In Part 2, we’re continuing the list with another 4 that are some of my personal favorites.
Penstemon digitalis – Foxglove Beardtongue
I have a special affection for the genus Penstemon. There is an enormous amount of diversity in the genus, much of which is native to the southwestern United States. They can be found in nearly every color including white, red, yellow, orange, blue, violet and deep burgundy-purple. Some species have very finely textured foliage while others are more strap-like or spoon-like. Perhaps the most common and well adapted to our area is Penstemon digitalis. In spring, the plant will produce a basal rosette of spoon shaped leaves followed by large 2-3′ stalks of tubular, white, bee-attracting flowers in May and June (sometimes later). After the blooms are finished, the stalks remain upright with seed pods that will remain through winter for interest if not cut back. Penstemon digitalis spreads readily from seed, but is generally not aggressive, only cultivating space that is not being used. If seeding becomes a problem, remove stems by August, before they begin to dry. Penstemon digitalis is very versatile, tolerating dry to somewhat wet soil and full sun to full shade. Best performance will occur in full sun to part shade with moist, well-drained soil. Some of the best cultivars of Penstemon digitalis include ‘Husker Red’ which turns a deep red in autumn, ‘Dark Towers’ which has dark foliage year round and a pink flower, and ‘Pocahontas’ with lavender flowers and dark foliage.
Asclepias incarnata – Swamp milkweed
Ever since planting this species in the garden, I’ve enjoyed the benefits of seeing pollinators flock to the flowers like flies to honey. My favorite visitor is the intimidating Great Black Wasp, Sphex pensylvanicus. If stinging insects are a concern due to the presence of children, I ask you to first take into consideration it’s size. Swamp milkweed often grows 4 to 5 feet tall and 2 to 3 feet wide. The pink flowers are borne at the top of the plants, far away from little hands, and since the plant is better as an accent in the midborder to background, some trampling and height adjustments will need to happen before children are put at risk. Swamp milkweed has a strongly upright to vase shaped habit with medium textured green to dark green foliage. The blooms typically appear between July and early September and are mildly fragrant. Plant in full sun with well drained to wet soil for best best results. Remove seed pods to prevent reseeding. While the plants will usually turn yellow in fall, you will sometimes get more interesting results. If you like swamp milkweed but need a smaller plant, try the variety ‘Cinderella’ which does not exceed 4 feet in height and has darker flowers.
My Asclepias incarnata turned shades of burgundy, red and yellow this past fall.
Mertensia virginica – Virginia Bluebells
Mertensia virginica is a wonderful spring woodland ephemeral that starts pushing out dusty violet to purple foliage in early April, followed by flowers before the start of May. The pendulous bell shaped flowers transition from pink to blue and occasionally occur as a very pale gray-blue. Plant Mertensia in full to part shade or under shade trees in masses for best results. When the plants are done blooming, they will set seed and die back to the ground. For this reason, it’s best to plant Mertensia with other shade loving perennials like Hosta which will fill the gaps left by Mertensia in late spring through fall.
The unopened flowers on Mertensia are pink to lavender.
Sporobolus heterolepis – Prairie dropseed
This native grass is already well beloved by many designers. The gentle sweeping nature of its leaves, along with its open airy panicles and orange-tan fall color makes it a favorite for adding a touch of grace or softness to a planting. Prairie dropseed typically produces 2-3 foot wide arching clumps and grows to about 3 feet tall, though the inflorescences may grow somewhat taller than that. When planting prairie dropseed, it is best to plant later in spring while the soil is warming as it is a warm season grass. Planting late is not usually a concern due its tolerance to extreme heat and cold, but it would be wise to mulch for late planting dates. The most notable thing about prairie dropseed may be its fragrance, which some say smells like popcorn, others say smells like cilantro or soap. If you like the idea of prairie dropseed but are looking for a slightly improved habit, I recommend ‘Tara’ which is a dwarf version with a more vase shaped habit.
There are many more natives suitable for the landscape and we’ll discuss them further throughout the season. In the meantime, join our conversation on Facebook. We want to hear from you, what are your favorite natives?
Tuesday, March 14th, 2017 at 7:00 am
When it comes to low maintenance plants, nothing beats native. Once established, natives have natural ways of tolerating drought, excessive watering, extreme winters, late frosts, trampling and grazing. There’s a problem with natives though. They can be difficult to manage. Sometimes they get too big or have a need to lean on their neighbors to look good. This bad reputation has drawn a lot of people away from natives, so today I’m going to talk about a few natives and “nativars” that are in a class of their own. Consider them trailblazers that will make you or your clients rethink native.
Parthenium integrifolium – Wild Quinine
When I first planted Wild Quinine, I had no idea what a gem I was getting. I originally added it to the garden because the coarse, upright leaves provided a much needed contrast to the fine textured foliage of Coreopsis and Perovskia. Then it bloomed. The large white flower heads emerge on 2-4′ tall stems in June through August (though sometimes earlier). The flowers remind me somewhat of pearly everlasting (but more attractive in my opinion). The flowers can be dried for winter arrangements or left in the garden for texture in winter. Plant this in well drained soil in full sun for best performance.
Tradescantia ‘Tough Love’ – Tough Love Spiderwort
The Pink Flowers of ‘Tough Love’ are different than many other garden species
Love is something you have to work at and Tradescantia ‘Tough Love’ is one of the best examples of what happens when you just keep working at it. Jim Ault, plant breeder at the Chicago Botanic Garden, introduced me to this pink flowering hybrid Tradescantia a few years ago and I’ve been waiting to get this into my garden ever since. Its parents, Tradescantia tharpii and Tradescantia occidentalis, are both native to the United States, but endemic to western and southwestern states. Unlike most Tradescantia that grow range-y and tall in moist, shady sites, ‘Tough Love’ prefers drier, sunnier sites, is compact and stays mostly evergreen throughout the season. The only maintenance it needs is a little cutting back at the end of the season.
Schizachyrium scoparium – Little Bluestem
The horticulture industry hasn’t ignored this native plant. It’s already available in a number of cultivars including ‘Carousel’, ‘Jazz’, ‘Prairie Blues, ‘The Blues’, ‘Jazz’, ‘Twilight Zone’, ‘Munchkin’, ‘Standing Ovation’, ‘Smoke Signal’ and more. The species grows anywhere from 2-4′ high and produces little brush-like inflorescences vertically along the plant. It tolerates a range of soils from dry to somewhat wet and does best in full sun, though will grow in part shade. It’s an excellent choice for rain gardens. The fall color on the species ranges from orange to purple and bronze, eventually turning tan for the winter. The plants tend to remain upright for much of the winter so it’s best to cut back when the snow melts.
Dalea purpurea – Purple Prairie Clover
The natural habit of Dalea in a wild area
When I want a little time to relax in the morning, one of my favorite things to do is visit Loyola Beach in Chicago’s Roger’s Park Neighborhood. The southern part of the beach is home to a decently sized dune restoration area and is planted with a wide variety of native plants. My favorite is the purple prairie clover. This upright to vase shaped perennial blooms from June until August (sometimes later), producing hundreds of tiny, pea-like, fuchsia to purple flowers on compact columnar inflorescences. The fine textured plant does best in full sun, with strong drought tolerance once established.
There are many more natives and “nativars” that are well suited to the landscape. Stay tuned in the coming weeks for more species and varieties that make the cut!
Monday, March 6th, 2017 at 8:46 pm
In the Do-it-Yourself (DIY) culture, there are few notions more alluring than crafting your own beer. In fact, the popularity of craft brewing has been increasing year after year for nearly the past decade. Searches on google for craft brewing reached an all time high in the United States in the summer of 2016. With the increasing popularity of craft brewing, there is a growing interest in the climbing perennial known as hops.
Humulus lupulus, or Hops, is an herbaceous perennial “bine” which spreads underground through rhizomes. Bines are similar to vines in that both climb fences and other vertical supports, but vines use tendrils or suckers, while bines grow in a helix (or spiral) and often have bristles to help them maintain grip. Careful attention should be paid when handling hops, as these bristles can have an irritating effect for some people. The rhizomatous habit of hops isn’t too often a problem, provided they are given an adequate structure to support themselves. If the plants do become too cumbersome, they’re relatively easy to split or remove, as the roots do not typically go very deep. The plants do exceptionally well in medium moisture soils in both sun and shade and will even tolerate dry shade.
The leaves of hops are lobed and somewhat resemble leaves of the grape family. I personally recommend Humulus lupulus as a non-invasive alternative for Ampelopsis brevipedunculata or porcelainberry. Though it is not as deeply lobed and lacks the showy berries, the foliage is still pleasing and the cones are delightfully fragrant. When winter comes, the vines of hops will die back to the ground. Simply cut them back and allow them to shoot the following spring.
Various leaf forms of hops
Photo by H. Zell via wikimedia commons
Hops first appeared in beer production in the 9th century, replacing older herbal blends. The preservative nature and strong fragrance of hops sealed its use in beer for the centuries that followed. The United States is one of the leading producers of hops, with much of the production on the west coast. If you or your customer wants to grow hops for beer production, look for varieties like ‘Cascade’, ‘Willamette’, or ‘Brewer’s Gold’. Ornamental varieties are much fewer in number and while you can use ornamental varieties for beer production, it’s not generally recommended.
Fragrant cones of hops
Photo by H. Zell via wikimedia commons
Beer production isn’t the only use for hops. The fragrant cones have long been used as a sleep aid and can be combined with other relaxing fragrances like lavender and chamomile to make a “sleep pillow” or “hops pillow.” Hops is also being researched for other medicinal uses including anaesthetic properties. The flowers of hops are also attractive to butterflies.
Female flowers of hops.
Photo by H. Zell via wikimedia commons
It is important to note that hops, like Ginkgo or Ilex, produce female flowers and male flowers on separate plants. If you’re growing hops for beer or for the fragrant cones, you must ensure that you have female plants.
Male Flowers of Hops
Photo by H. Zell via wikimedia commons
‘Aureus’ is an ornamental variety with chartreuse foliage and will produce cones on stems that will easily grow 15-25 feet high. ‘Sumner’ or Summer Shandy Hops has similar, though perhaps more striking foliage that will grow to about 10 feet in height. Summer Shandy has been grown for foliage and growth habit, and does not produce an abundance of cones.
Disclaimer: Hops are toxic to dogs. It is not recommended to plant hops in places that dogs may frequent.
Tuesday, February 28th, 2017 at 7:00 am
This Wednesday, billions of Christians will celebrate the holiday of Ash Wednesday, marking the beginning of Lent, a season of sacrifice. In the spirit of the Lenten season, I want to shine a spotlight on one plant that doesn’t require sacrifice: the Lenten rose.
Helleborus sp., also known as Hellebore, Lenten rose, or Christmas Rose, is really a landscape delight. You don’t need to worry about the sinister sounding “hell” at the beginning of it’s name. Helleborus comes from the Greek words for “food” and “to injure”, denoting that it is poisonous to consume.
In spite of its lack of culinary properties, it is safe to handle without the necessity of gloves.
Hellebores are among the earliest of bloomers, typically flowering between February and April. In the last few decades, breeders have made great strides in expanding the flowering time to extend anywhere from early November until June!
The Hellebore at the Chicago Botanic Garden blooms in spite of snow in December
In addition to the expansive bloom time, another benefit hellebore offers over other perennials is the huge range of colors offered in the hybrids. Many of the floral displays are multi-color within individual flowers, as well as across cultivars. The 3-4″ flowers are typically single but sometimes double, appearing in nearly every color including black! Sometimes described as orchid-like, the range and complexity of these flowers is incredible.
This perennial does best in part to full shade locations, with medium to medium dry soil. From April to November, glossy, evergreen, palmately compound foliage forms an attractive mound 1 to 1.5 feet high and wide.
A minor downside to this very hardy plant is that it may take some time to fully establish, so it is often best to lightly mulch around the roots to help stabilize soil temperatures and reduce any potential frost heaving. In spite of this, hellebore still does exceptionally well in the landscape. Almost no diseases plague this tough perennial, and it’s hard to imagine any could penetrate the sturdy foliage.
Helleborus ‘Ivory Prince’
If you haven’t grown Hellebores before, start with Helleborus ‘Ivory Prince’. This one is a customer favorite, well rated by the Chicago Botanic Garden. The chartreuse-white flowers have an attractive pink blush that may turn to a deeper rose over several months. The silvery-green foliage makes this one a bit easier to distinguish when the plant is not actively blooming.
Tuesday, February 21st, 2017 at 7:00 am
In our industry, every year comes with excitement, challenges and new opportunities.
We at Fiore are approaching the 2017 season with a sense of optimism. 2016 was a good year for landscaping and we grew as a company. We improved our operational efficiency, acquired land for our new branches, and introduced new people to our staff.
Our new land acquisition became our Bolingbrook location in Chicago’s southwest suburbs. The location will be better equipped to serve the Aurora-Naperville-Joliet area with the same great selection of plants, hardscape, bulk material and more. The new building is located at 801 N. Bolingbrook Drive, near Winston Woods park, North of Boughton Road. We’re currently working on improving our visibility from the road, so when you stop by for a visit, please keep your eyes open for our little building with the gray roof!
Come visit us in Bolingbrook!
Company wide, we are tailoring our business hours to meet consumer demand. To focus on our customers’ preference for morning and mid-day hours, we decided to begin closing at 4 PM. From April 1st until Thanksgiving, we will be open from 7 AM until 4 PM. We will be open Saturdays from April 15th to July 1st (7 AM to 12 PM). Our winter hours will remain the same, 8 AM until 4 PM. As always we will be closed for federal holidays including Memorial Day, Independence Day, Labor Day, Thanksgiving, and the following Friday.
We are also now in the final stages of releasing our new and improved Availability list. This digital list will be more readable and more regularly updated to make planning and ordering easier. We’re expecting this to be a big positive for the year! For those customers who prefer a physical list of our offerings, we will be printing a new Fiore Resource Guide which you can pick up at any of our offices for free.
Get ready, because some amazing new plants will be joining Fiore’s stock. One of my personal favorites is Magnolia ‘Genie’. This hybrid Magnolia is compact, only reaching about 15 feet in height over 10 years. Combine that with fragrant, velvety purple flowers and dark green foliage and it truly becomes outstanding.
I dream of ‘Genie’ and it’s beautiful purple blossoms.
You can also look forward to ‘Armstrong Gold’ Freeman Maples appearing in our yards as an alternative to ‘Armstrong’. ‘Armstrong Gold’ is a much fuller maple with brighter foliage and improved columnar habit.
‘Armstrong Gold’ gets the gold for it’s fuller habit.
We can also look forward to ‘Technito’ Arborvitae and ‘Starpower’ Juniper appearing in stock as well. ‘Starpower’ is an excellent upright Juniper that grows to about 17 feet tall, and a little more than half as wide. ‘Technito’ is a denser variety of Techny, said to require less shearing than Techny. It also grows to only about 10 feet, making it an excellent choice for screening a yard, while demanding minimal work!
‘Star Power’ Juniper has a strong upright habit
‘Technito’ is a great low maintenance sub for Techny in most residential settings.
We will have more announcements as the season progresses, so stay connected with our newsletter, Facebook and blog for more information.
What are you most excited about in the new year? Join our conversation on Facebook and let us know what you are looking forward to!
Tuesday, November 1st, 2016 at 7:00 am
Historically, the plants used on green roofs are as diverse as the places green roofs were created. Sod roofs were often overtaken with conifers and wildflowers over time in northern regions while Roman green roofs were commonly planted with Sempervivum. Today, I’m looking to explore some of the plants that have survived the green roof tradition and some of the best plants for our modern green roofs.
Sempervivum, commonly known to midwesterners as “Hen and Chicks” or “Live Forever”, was a required roof plant under the rule of Charlemagne. It was believed to ward off lightning strikes and fires, perhaps because of it’s green succulent appearance. This tradition of growing Sempervivum on the roof as a sort of good luck charm continues in some areas to this day.
Sedum is perhaps the most well known of green roof plants. Sedum love dry conditions and will develop aerial roots in more humid places. Groundcover Sedums such as S. spurium, S. acre, S. rupestre, and S. sieboldii are great groundcover species for covering large areas and are more commonin green roof applications. An evaluation study from the Chicago Botanic Garden found S. kamtschaticum, S. rupestre ‘Angelina’, and S. spurium ‘John Creech’ as some of the best sedum varieties for green roof application (of 16 sedum varieties trialed).
Phlox subulata, a common spring blooming rock garden plant excels on green roofs. Not limited to xeric conditions, creeping phlox has exceptional durability on the green roof and would likely do equally well on a sunny roof deck. Of three Phlox subulata varieties trialed at the Chicago Botanic Garden, all three earned 5/5 stars!
Junipers, like many conifers, is well adapted to the extreme conditions present on green roofs. Native to rocky and sandy areas in Canada and stretching from the New England states to Alaska, Juniperus horizontalis is one of the most rugged junipers. It is well adapted to tolerate extreme cold, heavy snow and drought, making it an excellent selection for a Chicago roof or roof deck.
Prairie Dropseed, Sporobolus heterolepsis, is one of my favorite grasses for it’s elegant swooping nature and light airy flowers. Nevermind the fact that it’s native, this grass is like a fountain spraying water in every direction. The flowers also have a fragrance similar to popcorn or cilantro. If the size and loose nature of Prairie Dropseed isn’t quite right for you but you like the look, try the cultivar ‘Tara’ which has a tighter, more upright habit, and smaller overall size.
This is a short list for some of the best options for green roof plantings.
For more suggestions on green roof plants, check out the Chicago Botanic Garden’s study here:
Tuesday, October 11th, 2016 at 7:00 am
The design of the green roof is very simple at heart. In ancient times it began with a solid base made materials such as stone or wood, then layered with waterproof material such as tar or birch bark. Following this, green roof builders placed a substrate such as sand or soil for plants to develop in. Finally, the green roof was planted with various herbaceous and woody plants until the desired effect was achieved.
Modern green roofs come in three basic types: intensive, semi-intensive, and extensive.
Extensive greem roofs have very shallow media for plants to grow in. As a result the plants grown in this kind of green roof tend to be sedum, sempervirum and other plants tolerant of xeric conditions. This type of green roof is the most economical choice for a roof. The cost of installation is low while maintaining the heat reducing and runoff reducing benefits. The media is typically 2-3″ deep.
An intensive green roof has a deeper substrate, allowing for a greater range of plants including various drought tolerant grasses, shrubs, and small trees. These are typically installed for aesthetic reasons, used as a park or even just a visual relief from a harsh cityscape. It often requires more maintenance but allows for the greatest amount of plant diversity. The growing media is typically 6-12″ deep. The Peggy Notebeart Museum and Chicago City hall are great examples of this type of green roof.
Semi-intensive is, as it sounds, an intermediate to the two types. The growing media is typically about 4-6″ deep, allowing for a number of hardy and drought tolerant perennials, grasses and small shrubs to be grown with minimal watering.
Besides the types of green roofs, its important to know about growing media. Notice I didn’t ever say soil? That’s because typical garden soils are much too heavy to transport to the tops of buildings. For this reason, it’s much more typical to see puffed or extruded clays, rockwool, and expanded slate used as the main component of growing media for green roofs. When combined with organic material, everything is there sustain plants throughout the years.