Why Winter Pelargoniums?
Successfully wintering pelargoniums is a rewarding practice that allows you to preserve these vibrant plants from one season to the next. Rather than treating them as annuals and replanting each year, many gardeners choose to overwinter their pelargoniums, especially prize specimens or those with sentimental value. This approach not only saves money but also ensures you have established plants ready to flourish when warmer weather returns. It's a critical step for anyone aiming for continuous displays of their beloved blooms.
The primary reason for wintering pelargoniums is to protect them from the freezing temperatures and harsh conditions of winter. In most climates, pelargoniums are tender perennials and cannot survive prolonged exposure to frost. By providing them with appropriate care during the dormant period, you prevent the plant from dying and set the stage for robust growth the following spring. This is particularly relevant for varieties that are expensive or difficult to source.
Beyond mere survival, overwintering can also encourage stronger growth in subsequent years. Plants that have undergone a period of rest often develop a more substantial root system and a sturdier framework, leading to more prolific flowering. It's a process that requires attention to detail but is fundamentally about mimicking, or at least facilitating, the plant's natural dormancy cycle in a controlled environment.
The success of overwintering hinges on understanding the plant's needs during its dormant phase.
Choosing Your Method
Several established methods exist for wintering pelargoniums, each with its own set of requirements and benefits. The choice often depends on the space available, the number of plants, and the gardener's preference for effort versus outcome. Broadly, these methods fall into categories of 'dormant storage' and 'semi-active care'.
Dormant storage is the most common and space-saving technique. It involves drastically reducing watering and light, and often pruning the plant back significantly, allowing it to enter a state of near-hibernation. This method is ideal for those with limited space, such as sheds, garages, or unheated conservatories. Semi-active care, conversely, involves keeping the plants in cooler, but still light, conditions with minimal watering and feeding, encouraging them to retain some foliage and potentially even produce the odd flower. This is often suited to unheated or minimally heated greenhouses.
A third, albeit more labour-intensive, option involves taking cuttings from healthy plants in late summer or early autumn. These cuttings, once rooted, can be grown on in cooler conditions and provide young, vigorous plants for the following season. This method also serves as a form of insurance if your main plants do not survive the winter.
- Protect pelargoniums from frost by bringing them indoors or to a protected space.
- Dormant storage saves space by reducing watering and light.
- Semi-active care keeps plants in cooler, lighter conditions.
- Taking cuttings is an alternative for young, vigorous plants.
Dormant Storage: The Space-Saving Approach
How do you store pelargoniums when space is limited? Dormant storage is the answer. This method focuses on drastically reducing the plant's metabolic activity to conserve energy and prevent damage from cold. It's a popular choice for gardeners with many plants or limited greenhouse facilities.
Preparing Plants for Dormancy
Begin by inspecting your pelargoniums for any signs of pests or disease. Any affected plants should be dealt with separately or discarded to prevent spreading issues. Next, prune the plants back quite hard. Aim to remove about two-thirds of the growth, leaving a framework of stems. This reduces the plant's overall size, making it easier to store, and encourages a bushier habit when it re-grows. Remove any remaining leaves, as these can hold moisture and encourage rot in dormant conditions.
For plants in pots, gently shake off as much of the old soil as possible without damaging the roots. You can then either repot them into slightly smaller, dry pots, or simply store them bare-rooted. If storing bare-rooted, gently tie the stems together in small bundles and hang them upside down in a cool, dry place, or pack them loosely into boxes with a little dry peat, sand, or sawdust. Ensure there's good air circulation to prevent mould.
The key to successful dormant storage is dryness and a cool, frost-free environment.
Storage Conditions
Ideal storage locations include a frost-free shed, an unheated garage, a cool basement, or a cold frame. The temperature should ideally remain between 5-10°C. Avoid storing them in a warm house, as this will encourage growth and weaken the plant. Check on your stored plants periodically – perhaps once a month. If the roots look excessively dry and shrivelled, you can lightly mist them with water, but avoid soaking the soil. The goal is to keep the roots just moist enough to prevent them from drying out completely.
When spring arrives and the risk of frost has passed, it's time to bring your pelargoniums back into life. Remove them from storage, trim off any dead or shrivelled growth, and repot them into fresh potting compost. Water them sparingly at first, gradually increasing watering as new growth appears. They can then be gradually acclimatised to outdoor conditions before being planted out.
Alternatives to Dormant Storage
If the idea of bare-root storage seems daunting, or you have a little more space, consider overwintering potted plants. Keep them in a cool, bright location, such as a frost-free greenhouse or a well-lit, cool windowsill. Reduce watering significantly, allowing the soil to dry out between waterings. You will still need to prune them back, but perhaps not as severely as for full dormancy. This method requires more light and slightly more attention but can result in plants that recover more quickly in spring.
Semi-Active Care: Keeping Them Ticking Over
What if you want to keep your pelargoniums growing, albeit slowly? Semi-active care offers a middle ground between full dormancy and keeping them as houseplants. This method is best suited for those with access to a frost-free greenhouse, conservatory, or a very bright, cool room that doesn't get too warm.
The Right Environment
The critical factor here is light and temperature. Pelargoniums need as much light as possible during winter, even if it's less intense than summer sun. A south-facing window or a greenhouse where temperatures are maintained between 7-13°C is ideal. Avoid placing them in a heated room, as the dry, warm air can encourage weak growth and attract pests like red spider mites. The cooler conditions slow down growth but allow the plant to photosynthesise and retain some vitality.
Watering should be minimal but more frequent than for dormant plants. Allow the top inch or so of soil to dry out between waterings. Overwatering is the primary danger, leading to root rot. If you see any signs of yellowing leaves or leggy growth, it usually indicates too much water or not enough light.
Maintaining a balance of cool temperatures and ample light is paramount for semi-active care.
Feeding and Pruning
Feeding is generally not required during the winter months for plants under semi-active care. Their reduced growth rate means they have minimal nutritional needs. Pruning can be done to maintain shape and remove any dead or weak stems, but it's usually less drastic than for fully dormant plants. You might even find that some varieties continue to produce a few blooms, offering a welcome splash of colour during the darker months.
As spring approaches, gradually increase watering and introduce a diluted liquid feed. Once the risk of frost has passed and new growth is evident, you can repot them into fresh compost and begin acclimatising them to outdoor conditions. This method can yield plants that are already well-established and ready to burst into flower as soon as they are planted out.
Considering Alternatives
While other flowering plants like begonias or fuchsias might require slightly different overwintering techniques, the principles of keeping them cool, dry, and protected from frost are often similar. For instance, begonias often benefit from a period of complete dryness, while fuchsias may need slightly more light if kept semi-active. Nasturtiums are generally treated as annuals, though in very mild climates they can sometimes survive, but they rarely perform well after overwintering. Sweet peas and marigolds are also typically grown from seed each year rather than overwintered.
If you notice your pelargoniums looking leggy and weak during their winter rest, try gently pinching out the growing tips. This encourages bushier growth when the plant starts its active season.
Reviving and Replanting
When is the right time to wake up your pelargoniums? The signal for revival comes with the approach of spring. As days lengthen and temperatures begin to rise, your overwintered plants will show signs of renewed life, prompting them to be brought back into active growth.
Signs of Life and First Steps
Look for swelling buds on the stems or the emergence of small, green shoots. For plants kept in full dormancy, this might be the first indication they are ready. Gently remove them from their storage, whether from bundles or pots. If stored bare-rooted, inspect the roots and trim away any that are completely dried out or rotten. Repot them into fresh, free-draining potting compost. Use a pot that is only slightly larger than the root ball to avoid waterlogging.
For plants kept semi-actively, you'll likely see more obvious new growth. Prune away any dead or weak stems to shape the plant and encourage a more compact, bushy habit. Water them thoroughly after repotting or pruning, but then allow the soil to dry out slightly before watering again. The aim is to encourage root development before strong top growth commences.
The transition from dormancy to active growth requires careful management of water and light.
Acclimatisation and Planting Out
Once new growth is well underway, the next crucial step is acclimatisation. Pelargoniums that have spent winter indoors or in protected spaces need to be gradually introduced to outdoor conditions. This prevents shock from sudden exposure to direct sunlight, wind, and fluctuating temperatures. Start by placing them in a sheltered spot outdoors for a few hours each day, gradually increasing the duration and exposure over a week or two. A cold frame or a porch can be useful for this intermediate stage.
Planting out should only occur once all danger of frost has passed in your area. Pelargoniums are sensitive to cold, and a late frost can undo all your wintering efforts. Choose a sunny location with well-drained soil. If planting into containers or hanging baskets, use a good quality potting compost. Water them in well after planting. With good care, your overwintered pelargoniums should reward you with a spectacular display throughout the summer.
Potential Pitfalls to Avoid
The most common mistakes are overwatering during dormancy, insufficient light in semi-active care, or planting out too early. Pests like aphids or whiteflies can also be a problem as plants start to grow, so regular inspection is wise. If you're growing plants like sunflowers from seed, remember they require a completely different approach, needing direct sowing or early indoor starting in spring and ample sun throughout their growth cycle.