Are you struggling to find shrubs and hedges that can withstand flooding and wet conditions in your New Zealand garden? Choosing resilient plants can save a fortune in constructing landscape drainage, or even worse, replacing established plants that die one year when the flooding is a bit more extreme than usual.
Understanding Flood-Tolerant Plants
Flood-tolerant plants are those that can withstand wet feet better than most plants, which will quickly die when exposed to excess water in the root zone. This includes some species which are well-known to tolerate wet feet, as well as cultivated varieties that have been bred specifically for this purpose.
Best Flood-Tolerant Plants Available in New Zealand
The below plant varieties have all been tested extensively in serious flooding conditions, and they all excelled. They’re also all drought-tolerant, making them perfect for areas like bio swales and depressed areas that rarely receive rainfall, but when they do, there’s too much to drain immediately.
Mundi™ Westringia fruticosa ‘WES05’ PVR
• Description: Mundi™ Westringia is a beautiful ground cover shrub that can be left unpruned while maintaining a tidy form or pruned into various low-growing architectural shapes. Ideal for tough roadsides or low maintenance gardens.
• Growth Habit: Low growing and requires less pruning.
• Size: 40-50cm high x 1.5m wide.
• Planting Density: 1-3 plants per m².
• Position: Thrives in full sun to part shade and suits sandy to well-drained clay soils. Tolerates cold and drought conditions.
• Where it Works: Suitable for both North & South Island regions.
Introducing Mundi Westringia. https://ozbreed.co.nz/plant-ranges/shrubs-and-ground-covers/mundi-westringia/
Grey Box™ Westringia ‘WES04’ PVR
• Description: Grey Box™ Westringia is a ground cover shrub that features grey-green foliage with white flowers, suitable for informal hedges or as a ground cover plant.
• Growth Habit: Low growing and compact.
• Size: 20-30cm high x 1-2m wide.
• Planting Density: 2-3 plants per m².
• Position: Flourishes in full sun to part shade and prefers well-drained soils.
• Where it Works: Ideal for coastal locations and inland gardens, North & South islands.
Introducing Grey Box Westringia. https://ozbreed.co.nz/plant-ranges/shrubs-and-ground-covers/grey-box-westringia/
Better John™ Callistemon viminalis ‘LJ1’ PVR
- Description: Better John™ Callistemon is a compact and hardy shrub with bright red bottlebrush flowers that attract native birds, making it a great landscape plant.
- Growth Habit: Compact and bushy.
- Size: 30-45cm high x 30-45cm wide.
- Planting Density: 1-2 plants per m².
- Position: Prefers full sun and well-drained soils.
- Where it Works: Well-suited for gardens, borders, and coastal areas.
Introducing Better John Callistemon. https://ozbreed.co.nz/plant-ranges/shrubs-and-ground-covers/better-john-callistemon/
Green John™ Callistemon viminalis ‘LJ23’ PVR
• Description: Green John™ Callistemon, a variety of Callistemon viminalis, is easier to grow and establish than Little John but slightly slower-growing than Better John™. It features small red flowers from mid to late spring.
• Growth Habit: Dense and moderately paced growth.
• Size: 60cm-1m high x 60cm wide.
• Planting Density: 3-6 plants per m², 2-2.5 plants per linear meter.
• Position: Thrives in full sun to part shade and prefers sandy to well-drained soils. Tolerant to drought and cold conditions.
• Where it Works: Suitable for planting in both North & South Island regions.
Introducing Green John Callistemon. https://ozbreed.co.nz/plant-ranges/shrubs-and-ground-covers/green-john-callistemon/
Macarthur™ Callistemon viminalis ‘LC01’ PVR
• Description: Macarthur™ Callistemon is a hardy and compact shrub bearing bright red bottlebrush flowers that attract native birds, making it an excellent choice for landscapes.
• Growth Habit: Compact and bushy.
• Size: 45-60cm high x 30-45cm wide.
• Planting Density: 1-2 plants per m².
• Position: Prefers full sun and well-drained soils.
• Where it Works: Ideal for gardens, borders, and coastal areas.
Introducing Macarthur Callistemon. https://ozbreed.co.nz/plant-ranges/shrubs-and-ground-covers/macarthur-callistemon/
Slim™ Callistemon viminalis CV01′ PVR
- Description: Slim™ Callistemon is a slender and upright shrub with vibrant red bottlebrush flowers, suitable for adding colour and attracting wildlife to gardens.
- Growth Habit: Slim and upright growth.
- Size: 1-1.2m high x 50-60cm wide.
- Planting Density: 1-2 plants per m².
- Position: Flourishes in full sun and well-drained soils.
- Where it Works: Well-suited for gardens, borders, and hedges.
Introducing Slim Callistemon. https://ozbreed.co.nz/plant-ranges/shrubs-and-ground-covers/slim-callistemon/
Best Practices for Planting
Providing practical tips on planting, drainage considerations, and maintenance techniques to support plant health in wet soil conditions. Best to plant when the soil is moist but not wet. Sometimes, it’s a good idea to water the night before planting. Assess soil conditions. Dig a hole twice as wide and exactly as deep as the root ball. Fill in the hole, adding amendments such as compost, manure, gypsum, hydrogels, kaolin clay, etc. Gently press the soil to remove air pockets without compacting the soil. Add amendments to the surrounding soil surface. Water well, but it’s best not to flood until plants are established. Cover the ground in mulch, leaving a gap around stems. Water again to settle the mulch.
Conclusion
Wet conditions can be hard to navigate in the garden as well as in landscape design. However, with the right plant palette of flooding-tolerant varieties, we can create landscapes that last the test of time.