Choosing the Best Native Plants for Rooftop Gardens

A rooftop garden can make a building much more pleasant.  These gardens keep a building cooler in the summer and warmer in the winter.  They improve the air quality, extend the useful life of a roof, and add beauty and color to urban areas.

Rooftop gardening is primarily done with buildings that have a flat roof, although sodding the roof and planting flowers can be done on slanted roofs.  Before buying your plants, it is important to make sure the rooftop can carry the extra weight of a garden.

Condition of the Roof

While it is possible to construct a rooftop garden on a normal city roof, it is not ideal.  You have to take into account all the roof’s flaws.  Water seeping in from the roof, roots growing into the roof, or other damage is common.

The best time to construct a rooftop garden is when the roof is being replaced or built.  This allows you to incorporate a water-proof membrane over the hard roof surface to protect the building below.  A root-resistant layer keeps roots from growing through the water membrane, creating leaks.

Structural Capacity of the Roof

Soil weighs a lot, especially when wet.  Add plants and the framing for each bed and the weight of a rooftop garden adds up.  You must hire a structural engineer or architect to examine the roof and decide how much additional weight the rooftop can support.  If the roof cannot take much weight, you may be limited to a few containers of native plants that live off of rainfall.  You can retrofit the roof to carry additional weight, but it is costly.

If the building is under construction, you can design the roof to hold a rooftop garden.  Installation is easier when it is a part of the construction, too, since cranes can lift the materials for the garden onto the roof without having to go through the elevator or stairs.

Access to the Roof

Access to the roof includes getting the garden supplies up to the roof.  Walking up several flights of stairs with lumber, soil, and fertilizer stops being fun very quickly.  In addition, most fire codes require two ways to exit the roof in case of fire.  This can be a fire escape, stairs, or access to the next building over.  Many rooftop gardens include a small greenhouse to start seeds in.  Greenhouses need electricity and the whole garden will need water so make sure those are available before planning yoiur garden.

Weight of the Garden

rooftop garden

An architect or landscape design architect needs to determine the weight of the kind of garden you want on your roof.  This takes into consideration the weight of water, soil, containers, heaters, cooling, ventilation, and, if it snows where you are, snow load.  You don’t want to get this wrong or your rooftop garden may become a basement garden.  You also have to consider how many people can be on the roof at one time.  Here are some estimates that the City of Chicago published for rooftop gardens.

  • Water stored in tanks weighs about 8 lbs/gallon.
  • Extensive green roof systems weigh about 20-34 lbs/ft2.
  • Intensive green roof systems weigh about 80-150 lbs/ft2.
  • The City of Chicago Municipal Code requires at least 30 lbs/ft2 for the design snow load.

An extensive green roof system is one where you use pots and some hardy plants for a garden.  It does not need as much infrastructure as an intensive green roof system.  An intensive green roof system is most like a raised bed garden on a normal lot.

Cost

A green roof system costs about 50% more than a conventional roof.  However, it extends the life of the roof by at least 50%, keeps cooling and heating bills lower, and looks nicer than a conventional roof.

Your budget needs to include the containers, cost of a structural engineer or architect for determining roof load and overseeing construction, safety features such as rails around the edge of the roof, transportation of materials to the roof, soil, an irrigation system, and the cost of permits and fees.  You should also include maintenance costs.  Some locations offer cost sharing if you put in a rooftop garden that meets their requirements because of the lower energy costs and pollution, but you will need quite a sum to get started.

Designing a Green Roof System

A green roof system has many components.  The bottom layer is the roof deck.  A waterproof membrane is next, then a root barrier to stop the roots from growing into the waterproof membrane.  A layer of insulation comes next, followed by a drainage layer that is gravel.  This gives the water from rain, snow, and irrigation of the garden a way to drain out of the growing media above it.  Next there is a filter mat that keeps the growing media from running out with the water as the garden drains.  Finally, there is the growing media, the plants, and a wind blanket to hold the growing media on the roof until the plant roots grow into it and prevent the wind from blowing it away.

Irrigation

Using plants native to the region you live in will decrease the need for irrigation.  However, there are times even drought tolerant plants need help, so you should provide a way to water your plants.  Drip irrigation is the best option, but a spigot for hand watering is the cheapest.  You will need to hire a plumber to extend the water system in the building to the roof.

Drainage

Drainage is essential to prevent the garden from damaging the roof and building.  Poor drainage not only causes the roots of your plants to rot, it adds substantial weight to the roof.  Most rooftop drainage systems can be used with minor tweaks.  Again, consult with a structural engineer or architect for help making sure your rooftop garden has good drainage.

Choosing Plants and Growing Media

Soil is heavy.  Most rooftop gardens use light weight growing media for their plants to grow in.  Typically, it is compost and lightweight, porous material that absorbs water and then releases it back to the plant as the plant needs it.  This medium is often referred to as potting mix, as it contains no soil.

Native plants fare best in rooftop gardens because they are adapted to the amount of rain the area receives.  Pick plants that can tolerate the wind, which can be substantial if the building is very tall.  Pick plants that are happy in poor, dryer soil so you do not have to fertilize them much.  You will have to water the plants the first year at least once a week until they are established.  The wind dries the soil and plants quickly, so a plant will require more water than the same plant in a garden on a regular lot.  Prairie plants such as purple coneflower, black-eyed susan, and blanket flower, since they can handle the wind better than something ephemeral, like a Virginia bluebell.

Maintenance

Plants need tending in a rooftop garden, just as if it were ground level.  Drains and gutters on the roof will need to be inspected more often than roofs without a garden.  Larger plants and trees will have to be pruned to prevent branch breakage in the wind.

We Can Help

TN Nursery specializes in native plants from across the United States and Canada.  Our specialists can answer your questions about choosing plants for your rooftop garden.  Simply call us at 931.692.7325 to get started.

Coneflower Plant - TN Nursery

Coneflower Plant

The coneflower plant, or echinacea, is known for its distinctive daisy-like, purple flowers with a prominent cone-shaped center. These flowers attract pollinators and add color to gardens.   Coneflower Perennial (Echinacea) Coneflowers, which resemble daisies, typically bloom in the middle to end of summer. Certain types may begin blooming earlier or continue into the autumn. They are available in a rainbow of hues, from yellow to deep pink, and with both single and double blooms that are incredibly vibrant. Magnus Superior variants bloom from the end of spring until the end of summer with rosy-violet rays that can reach a diameter of seven inches. These plants respond exceptionally well to deadheading. They spread gracefully like wildflowers thanks to their abundant seed production and self-sowing capabilities. Their delicate branches and colorful flowers make them perfect for gardens, where they provide visual interest without drawing attention to themselves. This naturalizing effect makes the plant look better and works well to fill in gaps between flower beds. Add Uniqueness to Your Garden With It Because of their unusual shape and composition, cones are a great way to add variety to your landscape. Their unique cone shapes also make them eye-catching accents among other garden plants. They provide textural variety to a garden by growing erect, contrasting wonderfully with trailing or mounding plants. In expansion, they can adjust to a broad range of soil types and light levels, giving you more alternatives for planting them. Invite Pollinators to Your Yard With It Since Coneflower Plants produce both nectar and pollen, many pollinators rely on these flowers for sustenance. Each 250 to 500 blooms that make up its black, cone-shaped flower head serves as a little cup of nectar for the pollinators. Bees and hummingbirds are just a few of the pollinators that love it. This variant can grow up to three feet tall and typically blooms between the middle of summer and the beginning of September each year because they produce seeds and are a popular nectar source for birds. They are of the same genus as the daisy, which you could guess by looking at. They bear stunning purplish-pink petals and are naturally drought-tolerant. As a native plant, they provide professionals and gardening enthusiasts with a low-maintenance option for adding complexion to outdoor spaces. What Do They Look Like?  The Coneflower (also called Echinacea) may be well-known for its petals' deep to pastel purple tinge. However, a closer look will reveal one of the most intricate and alluring central disks of all flowering plants. This flower gets its name from this striking and unique central disk.  It has received this moniker thanks to the spiny central hub. The spines are spread out in an almost exact order of distance, giving the cone a symmetrical shape and order that is truly stunning when observed closely.  In full bloom, their petals may splay out parallel to the ground or stretch downward. This positioning puts the central cone on full display and accentuates its bulbous shape. The spines on the cone can adopt a rust, red, orange, or yellow pigmentation throughout the blooming season.  Of course, the petals are nothing to sneeze at. Being a daisy gendaisieshe, the petals are lance-shaped and can grow to about 1.5 inches long. The flower is mostly an intense purple, where it connects with the stem and washes out gradually towards the tip. In some lights, this creates a pastel effect that is perfect for pairing with other flowers without drawing too much attention.  The stem grows erect and can reach heights between 2 and 4 feet. This makes this plant a great contrast to creeping or bunching plants. The leaves are basal and arranged alternately. They are a deep, cool green reminiscent of forest floors.  What Should You Plant Coneflowers If their chromatic and structural traits aren't enough to entice you, check out some of the more practical benefits of adding this flower to your landscape:  Planting Options: They are very versatile when it comes to planting. Once established, they are highly adaptable and can live with varying degrees of light and soil types. So, no matter what soil you have or what kind of space you have to work with, you can still enjoy these flowers. They Attract Pollinators. Hummingbirds and bees love the pollen and nectar they produce. The cone can house 250-500 spines, which are filled with food for a wide variety of pollinators.  Easy to Maintain - While they will require regular watering after planting, they only need a little maintenance after they are established. They respond well to deadheading, which can also help control seeding if you want them to spread only a little. They can handle several types of soil as long as it is well-drained.  They're Drought Tolerant - Want to contribute to the palette of your garden without spending a fortune on water? The plant is drought-tolerant. Once the roots have been established, maintaining them takes very little water. They Come in a Variety of Colors-They come in a bouquet of colors, from the typical purplish-pink to yellow shades. This makes them a popular choice for gardeners who want their landscapes to explode with color while maintaining strong uniformity.  Frequently Asked  Are you ready to start planting them in your lawn or garden? The following answers to commonly asked questions may prepare you.  When Do They Bloom?  The blooming season for them is typically between mid-summer and later summer. Some variants can bloom into autumn.  Do They Like Sun or Shade?  Like most flowers in the daisy family, daisies love sunshine. Planting them in an area with at least six hours of direct sunlight daily would help.  Do They Come Back Every Year? They are perennials, which means they come back every year. This makes them a good choice if you want to add consistent color and variety to your outdoor spaces.  How Tall Are They?  They can stretch to 2-4 feet tall. The stem holds the flower clear above the basal leaves, allowing it to be the show's star, even on the shorter end.  How Do You Plant Them?  Start by digging a hole twice the width of the root ball's diameter. The root ball should be set to level with the soil line. To help retain moisture, add a small amount of compost and mulch to the plant site. After planting, they will need regular watering until the plant has established.  Will They Bloom Again If Deadheaded?  Coneflower respond well to deadheading. They will bloom again if you deadhead them. There are particular advantages to deadheading. Firstly, it will keep them from overtaking other plants in your garden (deadheading prevents seeding). Secondly, it may prolong the bloom time.  How Do You Deadhead A Coneflower It will help if you always deadhead (prune) yours with shears, as the stems can be very hardy and rugged to snap by hand. Deadhead after the flower has faded, cutting it down to a leaf close to new growth.  TN Nursery Provides Year-round Beauty for Your  Whether you want the whole gamut of colors or lush greenery to add to your garden, TN Nursery has you covered. We offer many ferns, flowers, plants, mosses, shrubs, perennials, vines, trees, and more. Your order is backed up by a full, year-long, 100% satisfaction guarantee. Our prime specimens make planting and maintaining easy and allow you to enjoy the fulfillment of gardening. Place an order now and beautify your outdoor spaces. Where Does Coneflower Plant Grow Best  They grow well in soil that has good drainage and total sun exposure, meaning the plant requires at least six hours of direct sunlight per day. They are perennials and resistant to different environments; therefore successful in most climates but thrive well in a sunny garden with moderate watering.  How long do coneflowers take to grow  Coneflowers take 3-4 months to grow from seeds to flowering. When planted in early spring, they flower in mid-summer, and during early fall, they are on their third round of blooming.  What Does Coneflower Plant Attract  The flower is surrounded by tiny petals that attract bees, butterflies, and even hummingbirds.  Can you grow coneflower from cuttings?  Coneflowers are reproduced by seeds or by division, although it has been established that the plant can be propagated by cuttings. Propagation can be performed using softwood cuttings in spring or early summer and it is sown in a rooting medium and under constant humidity.  Can I Grow Coneflower Plant In Pots  Yes, coneflowers can be grown in containers so long as the pot has a drainage hole and sufficient size for root development. Select a high-quality nutrient-packed growing mix and put the pot in a well-lit area.

Black Eyed Susan - TN Nursery

Black Eyed Susan

Black Eyed Susan has vibrant yellow petals and dark, contrasting centers and is a popular and delightful addition to any landscaping project. This native North American wildflower offers a host of pleasing attributes that make it a sought-after choice for gardens and outdoor spaces. From its adaptability to its visual appeal and ecological benefits, it stands out as a versatile and attractive plant.  Black-Eyed Susan (Rudbeckia Hirta) Is A Long-Blooming Perennial  The Black-Eyed Susan or Rudbeckia Hirta is a beautiful and popular flower that blooms each year in North America. With yellow flowers surrounding a dark circular center, this plant serves an aesthetic purpose in any landscape and draws in bees and butterflies. Due to its hardiness and versatility, the plant is suitable for growing in the garden for beginners and professionals.  The Black Eyed Susan is valued for ornamental purposes and its contribution to the maintenance of ecosystems. Moreover, black-eyed susan plants for sale have stunning flowers that can be added to your garden for curb appeal. Features of Black Eyed Susan Plant The Black-Eyed Susan has bright yellow petals with a dark brown or black Eye in the middle, which makes it a vivid plant that would look great in any garden.  This plant attracts bees, butterflies, and many other beneficial insects, so it should be included in any pollinator garden. The black-eyed susan plant is relatively adaptable. It does well in arid conditions and simple soil types, making it a perfect pick for any low-maintenance garden. Black Eyed Susans Are Excellent Pollinator Plants It prefers regions receiving full or partial sun exposure. It has a growth habit of 2 to 3 feet tall with a similar width, enhancing the green appearance of areas where it is grown. This plant does not need much attention once established and usually grows well. It is relatively immune to many garden pests and diseases. Growers of black-eyed susan plants can also contribute to habitat and care for one's patch of land by offering food for pollinators and other more valuable insects. Black Eyed Susan Perennials Returns Every Spring and Summer Season Buy black-eyed susan plants and add these beautiful flowers to your garden, like our other popular ornamental plants, such as echinacea, shasta daisy, or coneflower plants. Where Does Black Eyed Susan Grow Best  Black-eyed Susans do well in regions of full exposure to the sun. Ensure they are exposed to a minimum of six hours of sunshine every day. They like well-draining soils and will grow in a range of soil types.  What Do Black Eyed Susans Symbolize  Black-eyed Susans symbolize encouragement, motivation, and justice. Their bright yellow color with a black center is linked with positivism and strength, perfect when integrated into any garden.  What Is The Best Fertilizer To Grow Black Eyed Susans Black-eyed Susans prefer a slow-release fertilizer, preferably a 10-10-10 N-P-K ration. Use it sparingly as they grow because these plants are not heavy feeders.  How Tall Do Black Eyed Susans Get  They are perennials that range in height between 1 to 3 feet, depending on their type. They provide great accents to borders and garden landscapes.  How Long Does It Take To Grow Black Eyed Susan  Black-eyed Susans can take from 60 to 90 days to bloom after germination from seeds. The plants come back year after year, blooming mid to late summer and continuing well into early fall.

Blanket Flower - TN Nursery

Blanket Flower

Blanket Flower is a perennial wildflower known for its vibrant, daisy-like blooms with red or yellow petals and dark center disks. Often found in prairies and gardens, it attracts pollinators and adds color to landscapes. This plant is the perfect choice when craving warmth. This radiant wildflower with an extended blooming season will light up your garden with a kaleidoscope of glowing colors.  Blanket Flower (Gaillardia aristata) Thrives In Drought and Full Sun Blanket Flower, or Gaillardia, is a sun-loving perennial with stunning two-toned daisy-like blooms. The name "Blanket Flower" interestingly comes from its warm yet vibrant red and yellow blooms, which are similar to the blankets Native Americans make.  This wildflower plant belongs to the Asteraceae (daisy) family and is native to North and South America. It is commonly found in Arizona, California, Arkansas, Indiana, Iowa, and Colorado. Blanket Flowers Resembles Daisy Perennials While it may resemble a daisy, blanket flowers are related to sunflowers and brighten up the dullest landscapes. The plant is usually paired with other drought-tolerant plants and showy grass to enhance the visual interest of the entire landscape. Moreover, blanket flowers for sale come in various warm shades and a few fabulous shades, making them a statement piece in the garden. Features of Blanket Flower Plant The plant grows best in total sun exposure, sandy areas, and poor soil. The poorer the soil, the more blooms it will grow.  The blanket flower features blooms in various colors, such as orange, purple, red, yellow, and White. Depending on the season, the foliage can be either blue-green or gray-silver.  This ornamental plant can reach 1-3 feet in height and 1-2 feet in width. Water the plant every other day during the first growing period until you see flowers. Once established, it's easy to care for and does not require regular watering to stay alive.  The Blanket flower is an ecosystem booster, so it loves pollinators, birds, and other wildlife Though people with sensitive skin may experience skin irritation, the plant is non-toxic to humans and animals. This vibrant perennial pairs well with low-maintenance and drought-tolerant perennials, like Butterfly Weed, Yarrow, and Daylily. So, along with blanket flower plants for sale, check out other companion plants at T.N. Nursery.  How Long Does A Blanket Flower Live  Blanket flowers live approximately 2 to 3 years in optimal climates and conditions. However, they self-seed and germinated every year and manifested their presence around the garden.  Why are they called Blanket Flower  They are named so due to the resemblance of their multi-colored and beautiful flowers to a patterned blanket. The flowers have lush reds, oranges, and yellows, providing a warm, bright view all through the season.  Does Blanket Flower Multiply  Indeed, blanket flowers reproduce both by seeds and by rhizomes. They can form larger clusters in time, giving the garden excellent bloom spots more often.  Does Blanket Flower Need To Be Deadheaded  Deadheading is not mandatory for growing blanket flowers, but this practice promotes more blooms and keeps the plants neat. Blanket flowers grow in well-drained soils and prefer minimal fertilization. During spring, you should only apply a small portion of a balanced fertilizer to encourage growth. Too much fertilizer may hamper the bright blooms.

Virginia Bluebell - TN Nursery

Virginia Bluebell

Virginia Bluebell is a spring-blooming wildflower native to the United States recognized for its delicate, bell-shaped, sky-blue flowers forming clusters and carpeting the forest floor in early spring. It is a captivating perennial plant that offers numerous benefits when incorporated into landscaping designs. Its enchanting appearance and adaptability have made it a favorite among gardeners and landscapers. Virginia Bluebell (Mertensia virginica) produces Sky sky-blue bell-shaped flowers These flowers start as shades of pink and gradually transition to a soothing sky-blue hue, creating a stunning gradient effect that adds a touch of elegance to any landscape. The lush green foliage further complements the vibrant blooms, enhancing the overall visual impact. Besides its visual appeal, it is positively adjustable to various soil types, making it a perfect option for landscaping projects in multiple environments. Its preference for partially shaded to fully shaded areas makes it ideal for underplanting trees or placing them along the edges of woodland gardens. This versatility allows landscapers to create visually appealing designs catering to light conditions. Another benefit of incorporating them is their role in supporting local ecosystems. These plants are attractive to pollinators such as bees and butterflies, making them valuable contributors to biodiversity. By attracting these pollinators, they aid in reproducing nearby plants and promote a healthier ecosystem within the landscape. They also require little maintenance, making them appealing to amateur and experienced gardeners. Once established, they require minimal care, allowing landscapers to focus on other design aspects. In conclusion, perennial plants offer a range of benefits that enhance the overall appeal and ecological value of landscaping projects. With their captivating appearance, adaptability to various environments, support for local wildlife, and low maintenance needs, these perennial plants are a valuable addition to any landscape design seeking a harmonious blend of beauty and functionality. Virginia Bluebell Is Known For Its Beauty  The Virginia Bluebell, or Mertensia virginica, is a stunning and delicate native wildflower that graces eastern North America's woodlands and meadows. This perennial plant, belonging to the Boraginaceae family, is renowned for its enchanting beauty and is often considered one of the most striking spring wildflowers in its native range. Standing at heights 1 to 2.5 feet, the wildflower is a herbaceous plant that emerges from the forest floor early to mid-spring. Its growth cycle is a true spectacle as it undergoes a remarkable transformation. Initially, the plant's lance-shaped leaves are tinged with an attractive reddish-purple hue, but as they unfurl, they transition to a soft, gray-green color, creating a stunning contrast with its vibrant blue flowers. The Virginia Bluebell Has Mesmerizing Fairy-Like Flowers The flowers themselves are the main attraction of the plant. They are composed of clusters of pendulous, trumpet-shaped blooms that are a breathtaking shade of sky blue or pale pink, depending on the soil conditions. These blossoms are unique because they start as pink buds, gradually shifting to their iconic blue hue as they mature. The floral clusters adorn the plant's upright stems, creating a sea of blue that sways gently in the spring breeze. One of their most remarkable aspects is their ability to thrive in shaded woodland areas. They are often found in the dappled sunlight beneath deciduous trees, creating a serene and ethereal ambiance in these natural settings. Their preference for moist, rich soils ensures they are frequently spotted along stream banks and low-lying areas. Aside from its visual appeal, it plays an essential ecological role. They provide nectar for early-emerging pollinators like bees and butterflies, helping to kickstart the pollination process for various plants in their ecosystem. The Virginia Bluebell symbolizes grace and fleeting beauty in the natural world.  Its striking blue flowers and unique life cycle make it a beloved harbinger of spring, enriching the landscapes it graces and captivating all who have the privilege to witness its brief but glorious bloom. What is the best fertilizer for Virginia Bluebells Virginia bluebells grow best under a light mulch of organic compost or the use of slow-release balanced fertilizer in early spring. As these plants prefer soils with natural fertility, fertilization may not be compulsory.  How often should I water Virginia Bluebells?  Irrigate Virginia bluebells often during their growing period to ensure the soil is wet but not saturated. They need less water once they have been established.  Can I grow Virginia Bluebells indoors Virginia bluebells are best suited for the landscapes but can be started inside in containers. These plants require only moderate lighting conditions and should be shifted outside only when weather permits.  What is the lifespan of Virginia Bluebells?  The Virginia bluebells are perennials, meaning that they will grow back year after year. If well taken care of, they can propagate and grow well and will do very well when placed in shaded garden sections where they will bring beautiful displays.  Where do Virginia Bluebells grow best Virginia Bluebells prefer moist, well-drained soil and in light shade or fully shaded conditions. They prefer a habitat similar to woodland settings.

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