In the temperate gardens of the UK, few sights are as instantly recognisable or satisfying as the pristine trumpet-shaped blooms of the calla lily. Their elegant form, often found in sophisticated whites but also in deep purples and vibrant yellows, brings a distinct architectural flair to borders and patio containers. For many gardeners, the central question remains practical and financial: do calla lilies come back every year in the UK, or are they treated as annuals, requiring a fresh purchase each spring?
Understanding the Botanical Nature of Calla Lilies
To answer whether these plants are perennial or not, we must first look at their true botanical identity. Despite their common name, calla lilies are not true lilies (Lilium) but are actually members of the Araceae family, known botanically as Zantedeschia. Their classification is the primary determinant of their growth habit in the UK climate. These plants are native to marshy regions of South Africa, which gives them specific environmental needs that differ significantly from hardy, woodland perennials.
The Verdict: Are They Hardy Perennials?
The straightforward answer to the question "do calla lilies come back every year UK" is nuanced. In the strictest horticultural sense, Zantedeschia aethiopica, the classic white calla lily, is a herbaceous perennial. However, for most gardeners outside of very mild coastal or urban microclimates, they do not behave as reliably hardy perennials that survive winter in the ground. The primary limiting factor is frost; while the rhizomes themselves are robust, they are not frost-hardy and will rot if left in waterlogged soil that freezes solid.
Outdoor Performance in the UK Climate
In a typical UK garden, if you plant a calla lily bulb directly into the ground in spring and leave it undisturbed through winter, the chances of it returning the following year are slim in colder regions. The crown and rhizomes will succumb to frost heave or rot in cold, wet soils. Consequently, many experienced UK gardeners treat them as annuals, enjoying their spectacular display for a single season and composting the tubers at the end of the autumn. For the truly dedicated, they will survive year-round only in specific zones or with significant protective measures, such as heavy mulching or lifting.
The Reliable Alternative: Container Growing
The most effective strategy for ensuring your calla lilies return annually is to embrace container culture. By growing them in pots, you gain complete control over their environment. During the main growing season, from late spring to early autumn, the tubes thrive in the warmth and moisture of a sheltered patio or balcony. As autumn temperatures drop, the simple act of moving the pot into a cool, frost-free greenhouse, garage, or shed is sufficient protection. This method transforms them into reliable perennials, as you can simply water them sparingly over winter and resume normal care in spring.
The Process of Lifting and Storing
For those who prefer to grow in borders or garden beds, lifting is the essential technique to mimic their natural dormant period. After the foliage has died back naturally in autumn, typically after the first frosts, the rhizomes should be carefully dug up. Excess soil should be shaken off, and the tubers left to dry for a few days in a warm, airy location. Once dry, they can be stored in cardboard boxes or paper bags filled with dry compost or sand and kept in a cool, dark place until it is time to plant them again in the following spring. This process ensures the tubers remain viable and disease-free, guaranteeing a return of their stunning blooms.
Maximising Flowering Year After Year
Whether you choose to overwinter in pots or lift and store tubers, providing the right conditions upon replanting is critical for success. Calla lilies are heavy feeders and thrive in nutrient-rich, moisture-retentive soil. Planting them with a generous amount of well-rotted garden compost or manure in the spring will provide the essential nutrients needed to produce those magnificent, show-stopping flowers. Ensuring they receive consistent moisture, especially during dry spells, and feeding them with a high-potash liquid feed every two weeks during the height of the growing season will encourage robust growth and prolific flowering, making the effort of overwintering well worthwhile.
