Introduction
Westringia plants, also known as coastal rosemary, have long been celebrated for their robustness, thriving in drought conditions and light, sandy soils. However, they’re not typically associated with a high tolerance for heavy clay soils or ‘wet feet’ conditions.
Despite this, some gardeners are keen to plant them in such challenging environments. This may be due to their desire for a native buxus hedge alternative, their knowledge of Westringia’s benefits to local wildlife, or simply their appreciation for the aesthetic appeal of these plants.
Regardless of the reason, there are a couple of Westringia cultivars that can withstand heavy clay soils and regular or sporadic flooding.
No, this isn’t trick photography. It’s a westringia thriving in wet feet. Grey Box™ Westringia fruticosa ‘WES04’ PBR
Why Westringia?
Westringia plants hold a special allure for many gardeners, landscape architects, and horticulture enthusiasts. Here are 20 reasons why these plants are so desirable:
- Native Appeal: As a native Australian plant, Westringia adds a touch of local charm to any garden.
- Wildlife Attraction: Westringia provides nourishment and shelter for native birds and insects.
- Drought Tolerance: Known for their ability to withstand dry conditions, these plants are perfect for water-conscious gardeners.
- Versatility: Westringia can be used as a standalone feature plant, as part of a mixed border, or even as a hedge.
- Low Maintenance: Once established, Westringia requires minimal care, making it ideal for those with busy lifestyles.
- Year-Round Interest: With its grey-green foliage and delicate flowers, Westringia offers visual interest throughout the year.
- Wind Resistance: Westringia is resilient in windy conditions, a trait that’s beneficial in exposed coastal gardens.
- Light Soil Adaptability: These plants thrive in light, sandy soils where others may struggle.
- Aesthetic Appeal: Westringia’s distinctive foliage and flowers add a unique aesthetic to any garden.
- Resilience: Certain Westringia cultivars can even tolerate heavy clay soils and ‘wet feet’.
- Salt Tolerance: Westringia can withstand salty winds, making it suitable for coastal gardens.
- Variety: There are numerous Westringia species and cultivars available, offering a wide choice for gardeners.
- Non-Invasive Roots: The root system of Westringia is not known to be invasive, reducing the risk of damage to nearby structures.
- Pruning Tolerance: These plants respond well to pruning and can be shaped to suit various garden designs.
- Buxus Hedge Alternative: Westringia provides a native alternative to traditional buxus hedges.
- Hardiness: Westringia plants are generally hardy and resistant to many common plant diseases.
- Fast Growth: Many Westringia varieties grow quickly, providing rapid coverage or privacy if needed.
- Evergreen: Being evergreen, Westringia provides colour and coverage throughout the year.
- Compact Varieties: For smaller gardens, there are compact Westringia cultivars that don’t compromise on beauty.
- Environmental Adaptability: Westringia has the ability to adapt to a variety of environmental conditions, making it a resilient choice for diverse landscapes.
These reasons illustrate the broad appeal of Westringia and why it continues to be a popular choice amongst experienced home gardeners, landscape architects, council decision-makers, and professional landscape experts.
The Challenge: Westringia in Heavy Clay Soils
Planting westringia in heavy clay soils presents a unique set of challenges. Clay soils are typically characterised by their fine, dense particles. Whilst they can be nutrient-rich, their compact nature often leads to poor drainage and a lack of oxygen, both of which are essential for healthy plant growth. These conditions are particularly challenging for westringia, a genus that’s naturally adapted to well-drained, sandy soils.
When planted in heavy clay, westringia may struggle to establish its root system. The compacted soil can restrict root growth, making it difficult for the plant to access the necessary nutrients and water. This struggle can lead to stunted growth and a general lack of vigour. Additionally, the poor oxygen availability in clay soils can lead to root respiration issues, further hindering the plant’s overall development.
A regular westringia that’s sitting in wet feet for any length of time is likely to develop a root rot disease such as Phytophthora, which can quickly lead to plant death.
As a result, gardeners must either drastically amend their clay soil to improve its structure and drainage (not always possible or affordable), or select westringia cultivars that have adapted to thrive in these challenging conditions.
The latter option is our focus, as we explore those westringia varieties that not only survive but thrive, even with heavy clay and wet feet.
The Unusual Suspects: Westringia Varieties that Thrive in Tough Conditions
Grey Box Westringia is a compact and hardy variety that stands out for its adaptability. Despite the general preference of westringia for sandy, well-drained soils, Grey Box Westringia can withstand heavy clay soils and periodic wet feet. This cultivar’s resilience paired with its attractive appearance – sporting white to light mauve flowers and grey-green foliage – makes it an excellent choice for challenging garden spaces.
On the other hand, Mundi Westringia is a low-growing ground cover shrub known for its toughness and aesthetic appeal. This cultivar can tolerate a range of difficult conditions, including heavy clay soils, wet feet, and even coastal environments. Its masses of white flowers and ability to attract native wildlife make it a valuable addition to any landscape, from council plantings to home gardens.
The survival of these cultivars in tough conditions can be attributed to several specific traits. Firstly, their robust root systems are capable of penetrating dense, compacted soils, enabling them to access necessary nutrients and water. Secondly, they have adapted to cope with the low oxygen levels often found in waterlogged soils, and have developed resistance to diseases such as root rot that typically affect plants in these conditions.
Mundi Westringia can get much larger than it’s supposed to when it’s constantly moist. Mundi™ Westringia fruticosa ‘WES05’ PBR.
Conclusion
The key to these Westringia cultivars’ survival in such challenging conditions lies in their robust root systems, adaptability to low oxygen levels, and resistance to root rot diseases like Phytophthora. These traits allow them to access essential nutrients, cope with waterlogged soils, withstand harsh weather and poor soil, and adapt to various environments.
So, don’t let heavy clay or waterlogged soils deter you from choosing westringias. With the right plant choices, even the most challenging garden conditions can be home to one of our native rosemaries.