Here is Jacksonville we were jumping for joy yesterday as we received approximately 35 - 40mm rainfall.
The rain yesterday was the first in two months. The area here has actually been officially designated as a 'Severe Drought' area by the National Weather Service.
Two green roof plants bear review under these conditions; Sedum acre and Phyla nodiflora.
|Phyla nodiflora, Turkey Tangle Frog Fruit Green Roof Plant|
|Sedum Acre, Green Roof Plant|
The above photographs were taken two days ago. Both plants have been established on a green roof for at least six month. They are not recent transplants. Both flourished earlier in the cooler temperatures.
An important note here before we proceed, even though Jacksonville may not receive much rainfall there are many afternoons this time of the year where water vapor is significant (high relative humidity) and temperatures on the green roofs are reaching for 66C (150F). Hot dry afternoons with high relative humidity toy with us gardeners as we watch the dark, afternoon clouds build only to fizzle out without a drop of rain.
The high air humidity both hurts and helps. Helping because any water in the air is good. Hurting because the hot wet air encourages Southern Blight Fungus and other fungi to grow and attack some of the green roof plants.
I love the name Turkey Tangle Frog Fruit (Phyla nodiflora) and Frog Fruit is a low growing groundcover plant native to the Americas, from Brazil to the Unites States. Frog fruit is acclimated to the high humidity and hot temperatures and fungus and drought, growing well under the harsh conditions.
Sedum on the other hand is beautiful during the cooler days when the high humidity and temperatures are not around to incubate Southern Blight and the other fungal culprits. But when those afternoon temperatures reach up into 'Hot' levels and the air water vapor content is high, Sedum may wilt as Southern Blight proliferates.
One could fill the air spraying fungicides across the roof, the chemicals drifting across the neighborhood to help keep the Sedum alive.
Sedum is not a native though.
I'm sure one day someone will genetically modify Sedum to be more like Phyla.
Phyla grows and keeps on growing despite the heat and humidity and lack of rain.
Sticking with native plants just makes sense. Especially on green roofs. I need to heed my own advice.