What is a Perennial and Do Calla Lilies Fit?
When asking 'are calla lilies perennials?', the answer is a qualified yes. Perennials are plants that live for more than two years, typically returning year after year to bloom. Unlike annuals that complete their life cycle in one season, or biennials that take two years, perennials have the remarkable ability to regrow from their root systems. This characteristic makes them a valuable addition to any garden, offering reliable beauty with less annual effort.
- Calla lilies are generally classified as perennials.
- They grow from rhizomes, which can survive through dormant periods.
- Proper care ensures their return each growing season.
- Climate plays a significant role in their perennial success.
The common calla lily, scientifically named *Zantedeschia aethiopica*, along with many of its hybrids and cultivars, falls into this perennial category. They store energy in underground structures, most commonly rhizomes (thickened underground stems), which allow them to survive unfavourable conditions like winter cold or summer drought. When conditions become favourable again, these rhizomes sprout new growth, producing fresh leaves and, eventually, their distinctive, elegant blooms. However, their ability to thrive as true perennials year-round is heavily influenced by their growing environment, particularly climate.
In regions with mild winters, calla lilies can often be left in the ground and will reliably return each spring. Their dormancy period might be less pronounced, with some leaf cover persisting. In contrast, colder climates require a different approach to ensure these tropical-originating plants survive the frost. This involves providing them with protection or overwintering them indoors, effectively mimicking their preferred warmer conditions.
Understanding Calla Lily Dormancy and Growth
How do calla lilies behave over the seasons? Their perennial nature is intrinsically linked to their dormancy cycle, which can vary significantly based on your local climate and how you manage them.
Seasonal Behaviour in Different Climates
In warmer climates (typically USDA Zones 8-11), calla lilies are often treated as evergreen perennials. This means they may continue to grow throughout the year, with perhaps a slight reduction in growth during the coolest months. They might go through a natural dormancy period in the height of summer if conditions become too hot and dry, but their rhizomes remain viable in the soil, ready to re-emerge with cooler temperatures or rainfall. You'll notice a cycle of vigorous growth, flowering, a period of reduced activity, and then a return to bloom.
In cooler climates (Zones 7 and below), calla lilies will not survive unprotected winters outdoors. They are not hardy in the way that many native perennials are. Instead, they must be treated as tender perennials. This means their aerial parts will die back with the first frost. However, the rhizomes themselves can be preserved. Gardeners in these zones typically dig up the rhizomes before the ground freezes, store them in a dry, cool, frost-free place over winter, and replant them in spring after the last danger of frost has passed. This artificial dormancy ensures they can be enjoyed year after year, even though they don't survive the cold season in the ground.
The primary factor determining if your calla lilies act as natural perennials is the temperature. If your garden experiences hard freezes, direct planting without protection will result in the loss of the plant. For those in suitable climates, leaving them in place allows them to perform their perennial magic.
Rhizome Care for Longevity
Whether you're in a warm or cold climate, understanding the rhizome is key. These are not true bulbs but rather underground stems that store nutrients. After flowering, the plant will naturally start to slow down. In warmer areas, this might be a summer lull. In colder areas, frost signals the end of the above-ground growth. Allowing the foliage to die back naturally, rather than cutting it immediately after flowering, helps the rhizome store maximum energy for the next season's growth. This nutrient replenishment is vital for ensuring the plant's return and continued vigour.
The potential for calla lilies to return year after year transforms them from a fleeting summer accent into a reliable, enduring garden feature.
If you are in a zone too cold for them to overwinter outdoors, the process of digging them up, cleaning them, and storing them requires a little attention. Ensure the rhizomes are dry but not desiccated, stored in peat moss or vermiculite, and kept at temperatures around 10-15°C (50-60°F). This careful handling is what enables many gardeners to enjoy their calla lilies as perennials, even when nature doesn't fully cooperate.
Are Calla Lilies Truly Perennial Like Other Flowers?
Comparing the perennial nature of calla lilies to more common garden perennials highlights their unique requirements. While flowers like hostas, daylilies, or peonies are reliably perennial across a broad range of temperate climates and require minimal intervention beyond seasonal tidying, calla lilies have a more specific set of needs.
Variations in Perennial Performance
The term 'perennial' can be interpreted differently depending on the plant's origin and hardiness. Calla lilies (*Zantedeschia*) are native to southern Africa, a region with distinct wet and dry seasons, and often considerable heat. This origin means they are not naturally adapted to frosty winters common in many parts of the UK or North America.
As a result, in many gardening contexts, they are classified as 'tender perennials' or 'tropical perennials'. This means that while they possess the biological capacity to live for multiple years and regenerate from their rootstock, their survival through winter depends heavily on external factors. If you live in a climate where ground frost is a regular occurrence, they will not survive the winter if left in the ground without protection, unlike truly hardy perennials. This leads to the common practice of treating them as annuals in colder regions or diligently digging and storing their rhizomes, a task not usually associated with plants like sarah raven tulips or allium plant seeds which are generally more robust.
Protect rhizomes from frost. If leaving them in the ground in borderline climates, a thick layer of mulch after the foliage has died back can provide enough insulation to prevent deep freezing.
Alternatives for Perennial Gardens
For gardeners seeking a more 'set it and forget it' perennial experience, especially in colder zones, other options might offer more straightforward perennial reliability. For instance, many varieties of Asiatic lilies or true lilies are hardy perennials that naturalise well, while tulips (like orange tulips, if planted appropriately) can also provide seasonal colour, though their perenniality can vary by type. Drumstick allium, for example, is a very reliable perennial that dies back in winter and reliably returns. If the primary goal is year-on-year bloom with minimal fuss, exploring plants that are naturally suited to your climate's winter conditions is often the most rewarding approach.
However, the exotic beauty and unique form of calla lilies make the extra effort worthwhile for many. When managed correctly, particularly through overwintering in colder climates, they unequivocally demonstrate their perennial nature, returning to grace the garden with their architectural presence and elegant flowers season after season.
Caring for Calla Lilies to Ensure They Return
Ensuring your calla lilies return each year as perennials involves understanding their needs regarding water, light, and temperature. Their success as long-lived plants hinges on providing conditions that mimic their native habitat as much as possible, especially regarding their dormant periods and growth phases.
Watering and Feeding
During the active growing season, calla lilies appreciate consistent moisture. They are often found growing in damp conditions in their native habitat, so keeping the soil consistently moist, but not waterlogged, is ideal. Overwatering can lead to rhizome rot, especially in cooler, less actively growing conditions. As the plant naturally enters its dormant phase, either due to heat and drought or the onset of autumn, watering should be significantly reduced. For those overwintering rhizomes indoors, they should be kept dry during their storage period. Regular feeding with a balanced liquid fertiliser throughout the growing season will support strong growth and abundant flowering, helping the rhizome store adequate energy.
The key to continued perennial performance lies in respecting their need for a rest period. This dormancy is as crucial as their active growth phase for long-term health and vigour. Neglecting this can weaken the plant and reduce its chances of returning successfully.
Light and Soil Conditions
Calla lilies thrive in bright, indirect light or partial shade. Direct, hot afternoon sun can scorch their leaves, particularly in warmer climates. A location that receives morning sun or dappled shade throughout the day is often best. They prefer rich, well-drained soil. Amending the soil with compost or other organic matter will improve its structure and fertility, providing a good environment for the rhizomes to establish and grow. Ensuring good drainage is paramount to prevent the rhizomes from sitting in water, which can lead to fungal diseases and rot.
When planting rhizomes in spring, place them about 10-15 cm deep with the growing points facing upwards. Spacing them appropriately allows for good air circulation and room for the plant to mature. For those in regions where calla lilies are planted directly into garden beds, consider the soil quality and drainage. Raised beds can be an excellent solution for improving drainage if your garden soil is heavy clay. This attention to soil and light ensures the plant establishes a robust root system, which is the foundation of its perennial life cycle.