The first image that comes to mind when we hear drought resistant plants is a dry desert, with prickly cacti and hard rock landscapes. What you might not know is that plants that have less water needs are some of the most beautiful ones that can be grown! Xeriscaping helps us achieve this.
What is xeriscaping?
It is a type of landscaping which needs little to no water.
It was first followed in hot and dry climates which faced scarcity of water. It has started gaining traction in other parts of the world.
It involves growing xerophytes, slow growing plants that need minimal water. They are more than just spiky cactuses and include beautiful flowers and decorative shrubs.
Significance of xeriscaping
Green spaces are necessary everywhere, especially in an urban setting.
Interaction with nature is beneficial for health and helps us relax and rejuvenate.
With the increase in population, lesser availability of resources and rise in global warming, integrating green spaces in the urban areas has become difficult, but it is crucial.
Following methods like xeriscaping ensures that minimal resources are spent in growing plants.
Favorable in the current water scarce situation as xerophytes require 50-75% lesser water than traditional plants.
Retains plants that are necessary in urban landscape even when the place faces water shortage.
Maintenance is mostly limited to weeding and pruning as the plants used are mostly local and already adapted to the surroundings.
Better for the environment due to the reduced use of fertilizers and herbicides. Organic soil can be used to grow healthy xerophytes.
It brings down costs by 50% as there is no need for supplements, fertilizers, labor or other maintenance.
When the correct plants are chosen, xeriscaping transcends cactuses and rock landscaping and adds to the aesthetics of the building.
Consider site factors like slope, drainage, wind, sun exposure, views and future built structures before deciding the location of the xeriscape.
Soil should have high organic matter and ability to conserve moisture should be used.
Well aged manure and compost can be used to treat the soil before planting.
Xerophytes have deep root systems so it is essential to use soil that allows penetration.
Plants native to the site should be given preference as they need lesser external resources to adapt and grow.
The plants must be drought tolerant and should require less water.
For turfs, consider the size and shape of the area and also factor in if the turf will have high or low traffic.
Shredded wood and bark chips can be used in mulch planting beds.
They keep the plant roots cool, prevent water evaporation, reduce weed growth while being aesthetic.
Rock and gravel can also be used as inorganic mulch.
Rocks should not be used extensively as they can raise the temperature around the house, result in poor plant health and cause wasteful water runoff.
Processes like mowing, trimming, pruning and fertilizing the plants should be done in timely intervals to ensure that they grow correctly.
The best method to water xerophytes is by creating hydrozones.
The plants and turfs are grouped according to their water needs.
The categories are-
High (regular watering)
Moderate (occasional watering)
Low (little to no watering)
By creating zones, appropriate watering systems can be used to cater specifically to the plants based on their needs and hence reduce water wastage.
Plants that need very little water survive on rainfall.
Some of the irrigation methods are-
They are most commonly used and best suited for turfs.
They could be hose end or permanent underground sprinkler.
Both the systems require little maintenance but apply large amounts of water in a short period of time.
The sprinkler should be adjusted such that it waters the required areas only.
Large droplets should be sprayed, as fine mists are susceptible to evaporation and wind drift.
In this method, water is supplied gradually.
At each plant, water flows under low pressure through emitters, bubblers or spray heads.
This method reduces water wastage due to evaporation or surface runoff.
Types Of Xeriscaping
Here are some common xerophytes that can be put to use based on types
japanese black pine
Succulents with colorful leaves
Pink jelly bean
Succulents with colorful flowers
Hardy ice plant
It is necessary to factor in the environmental conditions while designing buildings and ensure that each step that we take is sustainable. Xeriscaping is the best method to landscape sustainably.
Case study of Xeriscaping – California Academy of Sciences
Located in San Francisco, this building supports a 2.5 acre green roof for which it has a LEED platinum certificate.
The natural landscape has been taken to the next level, raised 35 feet up and placed on the roof of the building.
The roof is undulating, assuming different heights based on what function the space below serves. It rises high over the planetarium and rain forest exhibit and lowers in the central piazza, allowing light into the building.
The seven hills on the roof are a reflection of the seven hills of San Francisco.
The plants on the roof are majorly xerophytic, native to California and adaptable to the area’s irrigation cycle. This makes the roof highly sustainable.
The plants were also selected such that the roof attracts butterflies, birds and insects, including endangered species.
Wild Rose, Blackberry ,Black Sage, Sonoma Sage, Hummingbird Sage, Bee Plant, Stonecrop ,Blue-Eyed Grass, Golden-Eyed Grass are some of the xerophytes on the living roof.
The roof is completely natural with no mechanical interventions.
An underlying grid of gabion channels act as water drainage and support for the coconut husk planting trays.
The plants are potted off site and placed over layers of insulation and the support structure.
The coconut husk trays are lined like tiles over the roof and allow roots to grow, forming an interconnected patchwork. The trays eventually break down and act as manure.
All the runoff stormwater is collected and used to recharge the water table.
Photovoltaic cells line the roof and generate energy to power the building.
Open air observation terraces allow visitors to closely interact with the native species and learn about them.
The roof provides great insulation, reduces interior temperature by 10 degrees, reduces noise by 40 decibels and reduces urban heat island effect.