Do shade plants require constantly wet soil?
Written by
Michael Sullivan
Reviewed by
Prof. Samuel Fitzgerald, Ph.D.Common myth in gardening: Shade plants need constantly wet soil, or they will dry up and die! Wrong. Many of the plants that are adapted to shade, such as Bigroot Geranium and Brunnera learn to be drought tolerant and are found living in arid areas under shade, where they grow splendidly.
The explanation of this drought resistance is found in plant physiology. The roots are penetrating and reach moisture below the surface when the top layer becomes parched. Species with waxy leaves lose little humidity through evaporation, and those with hairy foliage collect moisture from the atmosphere; these arrangements facilitate easy weathering without excessive soaking.
Bigroot Geranium
- Develops deep roots reaching 18-24 inches into soil
- Waxy leaf coating reduces water loss by 30-40%
- Survives 3+ weeks without water after establishment
Brunnera
- Hairy leaves trap humidity from the air effectively
- Thick rhizomes store water for extended dry spells
- Performs well in zones 3-8 with minimal irrigation
Ajuga
- Forms dense mats that reduce soil evaporation
- Leathery leaves resist wilting during drought
- Thrives under trees where rainfall is limited
Natural drought resistance is enhanced by proper soil preparation. Enrich planting sites with a small amount of organic compost. The planting holes should be slight depressions so that rain will collect in them. A small amount of mulch will help to keep the soil moist. All these steps protect the plants as they become established.
Understanding of microclimate helps us to avoid overwatering. North-facing slopes hold water longer than the ground beneath a tree. Competition from the roots of the tree causes the surrounding soil to dry out. With that in mind, place drought-tolerant plants in the naturally dry spots where they will thrive with minimal watering.
Seasonal care modifications ensure the health of plants. Water new plants consistently, about once a week, during their first season (June-September). After roots are established, reduce watering gradually. Mature plants only need watering during extreme drought conditions. This type of watering maintains conditions as they would occur in nature (roots grow toward moisture), which helps plants become resilient!
Common signs of over-watering are yellowing leaves and root rot. Be sure to check your soil moisture before watering new plants in the ground. Insert your finger about two inches deep; if the soil feels dry, water. This practice will help you avoid problems related to excess moisture in shade gardens.
Read the full article: 10 Best Flowers for Shade Gardens
