The best roof garden plants are low maintenance and able to survive the harsh conditions present on rooftops. Urban rooftop gardens make exquisite spaces that can be surprisingly low maintenance, if you use a good mix of the best roof garden plants.
Rooftop Garden Plants Must Withstand These 2 Things
High Heat Exposure
Roof gardens are exposed to a lot of heat on a regular basis. That means plants must be tolerant of high heat and sun.
High Wind Exposure
The taller a building is in relation to its surrounding buildings; the more susceptible roof top gardens are to high winds.
Key Characteristics Many of the Best Roof Garden Plants Share
They have tap roots
Plants with tap roots are defined by the fact they can store moisture in specialized root tissues. Examples of tap root plants include Butterfly Weeds, False Indigo, and Coneflowers.
They have furry leaves
Plants with fuzzy leaves and silver foliage tend to show slower evaporation of water from leaves. This helps them withstand a lot of heat and direct sunlight without drying out as quickly. Good examples of furry leaf plants for rooftops include sage and lavender flowers.
They are part of the succulent plant family
Succulent plants are hardy as heck! They store excess moisture in their leaves, which allows them to survive harsh dry conditions—hence why they are a popular desert plant. Some examples of succulent plants that grow well in containers include yuccas and stonecrops.
The Importance of Hardiness Zones for Rooftop Gardens
Rooftop plants are exposed to harsher conditions than plants on the ground. It’s not just the sun. Container plants are more susceptible to chill in the winter compared to in-ground plants because they don’t have as much soil protecting their roots. As a result, look for plants that are approved for at least one to two hardness zones colder than your region.
What About Rooftop Garden Trees?
Evergreen trees and shrubs are commonly used to outfit rooftop gardens because of their hardy and drought-resistant properties. Thanks to compact leaf surfaces, these trees and shrubs lose water slowly. Plus, the waxy residue on foliage offers an extra barrier against high winds that can otherwise dry out plants. Some great evergreen trees include Oregon grape, junipers, and arborvitae.
The Kousa Dogwood tree is hardy to Zone 5 and is considered a small tree but can grow as large as 30-feet. The tree contains a variety of small white and pink flowers, which turn a vibrant green in the summer. During fall, the tree sprouts with red-purple leaves and fruit.
Harry Luader’s Walking Stick adds dimension to any space thanks to its twisty roots. The tree/shrub produces a round, heart-shaped foliage. It can grow as tall as 10 feet. Hardy in Zones 4-8. Keep in mind, this plant is considered invasive in some areas.
Diverse Plants for Rooftop Gardens
Some portions of your rooftop garden might be shadier than others. If you have a great shady spot you might want to consider planting Big Daddy Hosta. The leaves on this plant are impressive due to their bright blue-green coloring and monstrous size. Hardy in Zones 3-8, this is a great filler plant for shaded portions of your rooftop garden.
What about rooftop vines? Climbing hydrangea is an excellent option if you want to add vines to your rooftop garden. This type of self-adhering plant vine blooms with delicate white flowers and can reach up to 60-feet in length. Approved for hardy Zones 4-8; this is a low maintenance plant that offers beautiful color in autumn and spring.
How to Water Rooftop Plants
A drip irrigation system is a great way to manage rooftop gardens. You may also want to consider investing in self-watering planters. This will help prevent plants from soaking up too much water—in the instance there’s a storm or someone overwaters them. It also prevents root rot because water builds up in a chamber underneath roots, as opposed to in the soil with the roots.
Self-watering planters are beneficial in the summer too, as they can help prevent plants from drying out. The water collection chamber can be accessed when the roots extend down.
What Type of Planters Should You Use for Rooftop Gardens?
If it gets cold in the winter, you need solid winter-proof planters. Many planters are not made to withstand freezing cold temperatures and will crack as a result. For hot summers, the right materials matter to help prevent plants from drying out quickly. Additionally, you don’t want to get too much weight on a roof, and that’s where lightweight planters come in handy. Plus, lightweight planters are easier to transport on top of your roof in the first place.
Our planters are made to withstand the harsh conditions experienced on rooftops—from heat, to cold, and everything in between. No one makes a more durable planter than us. Plus, they are made right here in the USA!
Shop our huge selection of commercial and residential planters here: https://www.terracastproducts.com/our-shop/planters/