Why March is Key for Planting Perennials
March is a pivotal month for gardeners, signifying the transition from winter's dormancy to spring's awakening. While the weather can still be unpredictable, with potential for frost, it offers a crucial window for establishing new perennial plants. Planting perennials in March allows them to develop strong root systems before the heat of summer arrives, ensuring better establishment and long-term health. This early planting also means you can often take advantage of dormant or semi-dormant specimens, which are frequently more robust and less stressed when transplanted. Choosing the right perennials for planting in March is about selecting varieties that can tolerate cooler soil temperatures and occasional dampness, setting the stage for a garden that bursts into life throughout the seasons.
- Planting perennials in March establishes strong root systems early.
- March planting helps plants withstand summer heat better.
- Dormant plants transplanted in March often establish more robustly.
- Select varieties suited to cooler, potentially damp, spring soil.
The soil, though cool, begins to warm sufficiently in March to encourage root growth. This is a vital period for preparing your borders for the coming display. Unlike summer planting, which can stress plants in hot, dry conditions, early spring planting offers a more forgiving environment. It provides ample time for roots to spread and anchor the plant, making it more resilient to drought and disease later in the year. Considering what to plant now can significantly impact your garden's success for months to come. While some gardeners might favour planting spring bulbs for later blooms, establishing perennial roots in March provides a foundation for ongoing colour and structure.
Inspect plant roots before purchasing; plump, white roots indicate a healthy specimen ready for planting now.
Understanding Perennial Planting Windows
Perennials are plants that live for more than two years, typically dying back in winter and regrowing in spring. Their planting windows are generally dictated by the soil temperature and the plant's hardiness. Autumn is often considered the best time for planting many perennials, allowing roots to establish over winter. However, March offers a secondary, highly effective planting opportunity. It's particularly suitable for hardy perennials that can withstand cooler conditions and for those you might have overwintered as bare-root plants or in pots. The key is to assess local conditions; if the soil is workable and not waterlogged, March is ideal. This contrasts with tender plants or summer-flowering bulbs which require warmer soil or later planting.
Benefits of Early Spring Planting
The primary benefit of planting perennials in March is the chance for roots to establish before the growing season truly accelerates. This means plants are less likely to suffer from transplant shock and are better equipped to draw moisture and nutrients. It allows gardeners to get ahead, filling gaps and expanding borders with a diverse range of flowering plants and foliage. Furthermore, many nurseries and garden centres offer a wide selection of perennials at this time, often including varieties that are best planted while dormant or semi-dormant. This timing also allows for better soil preparation, as you can incorporate compost and other soil improvers before planting, creating an optimal environment for your chosen plants.
Top Perennials to Plant in March
When considering perennials to plant in March, focus on varieties known for their resilience and ability to establish quickly in cooler soil. These plants will repay your early efforts with vibrant displays throughout spring, summer, and into autumn. The goal is to select plants that thrive in your specific garden conditions, whether that's sun, shade, or dappled light, and whether your soil is well-drained or holds more moisture. This selection covers a range of colours, forms, and flowering times, ensuring continuous interest.
Hardy Perennials for Immediate Planting
Many hardy perennials are perfect candidates for March planting. These are plants that can tolerate frost and cooler temperatures, making them ideal for establishment in early spring. Consider plants like:
- Hostas: Especially valuable for shady borders, their foliage offers texture and colour. Plant divisions or potted specimens now.
- Daylilies (Hemerocallis): While they bloom later, planting divisions in March allows them to establish well for a summer show.
- Astilbes: Suited for damp, shady spots, their feathery plumes add delicate texture.
- Echinaceas (Coneflowers): These popular prairie plants benefit from early planting to establish strong root systems for summer blooms.
- Rudbeckias (Black-eyed Susans): Similar to Echinaceas, early planting encourages vigorous growth.
- Geums: Offering early to mid-season colour, Geums are generally hardy and respond well to March planting.
- Pulmonarias (Lungwort): These early spring bloomers are perfect for shady, moist areas and can be planted now.
Flowering Perennials for Early Colour
While many perennials bloom later, some offer early interest or are best planted now to ensure a good display. For instance, although often associated with autumn planting, some spring-flowering bulbs like daffodils and tulips, if planted very late or if overwintered, can still be planted if the ground is workable. However, focusing on perennial roots is more typical for March. Plants like Hellebores, while often bought in flower earlier, can be divided and replanted in March if needed. New divisions will establish for future years. For vibrant spring and summer colour, consider introducing plants that will mature quickly.
Perennials for Specific Conditions
When selecting perennials to plant in March, it's crucial to match them to your garden's microclimate. For sunny, well-drained borders, hardy geraniums, Salvias, and Nepeta (Catmint) are excellent choices that establish readily. In shadier, more sheltered spots, Ferns, Dicentra (Bleeding Heart), and Brunnera thrive. For areas prone to dampness, even after winter rains, plants like Iris sibirica or certain varieties of Lysimachia can be successfully planted. The key is to assess your soil type and light levels before making selections.
The most successful gardens are built on thoughtful plant choices that align with local conditions, especially when planting during transitional seasons.
Consider plants that might have been overwintered in pots. These can be transferred directly into the ground in March, providing an immediate presence in your borders. This is particularly useful for larger specimens or those that benefit from a slightly more protected start. Remember, the aim is to provide conditions where the plant can establish its roots, making it less dependent on constant watering as the season progresses.
Preparing Your Soil for March Planting
Effective soil preparation is paramount when planting perennials in March. The goal is to create an environment that supports robust root development and aids drainage, especially given the potential for increased rainfall at this time of year. Neglecting this step can lead to waterlogged roots and stunted growth, undoing the benefits of early planting.
Improving Soil Structure and Drainage
Most garden soils benefit from the addition of organic matter. Before planting, dig over the area where your perennials will go to a spade's depth. Incorporate well-rotted compost, leaf mould, or well-matured manure. This improves soil structure, making clay soils more workable and sandy soils better at retaining moisture. Good drainage is critical; if your soil is heavy clay and prone to waterlogging, consider adding grit or perlite to improve aeration and drainage further. Raised beds can also be an excellent solution for areas with persistently poor drainage.
For new beds or borders, it's advisable to clear out any perennial weeds thoroughly. Their roots can compete with your new plants for nutrients and water. Ensure you remove as much of the root system as possible to prevent regrowth. Taking the time to prepare the ground properly now will significantly benefit the long-term health and vigour of your perennial plants.
Incorporating Nutrients
While organic matter provides essential nutrients, you might also consider a balanced, slow-release fertiliser. This should be mixed into the soil during preparation, rather than applied directly to the plant roots, to avoid burning. A fertiliser with a balanced NPK ratio (Nitrogen, Phosphorus, Potassium) will support overall growth, root development, and eventual flowering. However, avoid over-fertilising, as this can lead to weak, leggy growth that is more susceptible to pests and diseases. The focus for March planting is on establishing a strong foundation, so nutrient availability is important, but balanced growth is key.
Always check the specific needs of the perennials you have chosen. Some, like those adapted to poor soils, may require less nutrient-rich amendments. Over-enriching their soil can be detrimental. Understanding the plant's native habitat can offer clues as to its ideal soil conditions.
Assessing Soil Workability
Before you begin digging, perform a simple workability test. Take a handful of soil and squeeze it. If it forms a tight, sticky ball that doesn't crumble, it's too wet to work. If it falls apart into dry crumbs, it's too dry. Ideal soil will form a loose ball that can be gently broken apart. If your soil is too wet, wait a few more days or weeks for it to dry out sufficiently. Working soil when it's too wet can damage its structure, leading to compaction and poor aeration.
Planting Techniques for March Perennials
Once your soil is prepared and your chosen perennials are ready, the planting process itself is relatively straightforward. However, employing the correct techniques ensures your plants get the best possible start, maximising their chances of successful establishment and future growth. This is particularly important when planting in March, as the plants are often still in a semi-dormant state and need careful handling.
Planting Bare-Root and Potted Perennials
Bare-root perennials, such as many roses, fruit bushes, and some herbaceous plants, are typically supplied with their roots exposed. These should be planted as soon as possible after delivery. Before planting, it's often recommended to soak the roots in a bucket of water for a few hours (but not more than 6-8 hours, as prolonged soaking can be detrimental). Dig a hole wide and deep enough to accommodate the spread of the roots without bending them. Create a small mound of soil in the centre of the hole and spread the roots over it. Backfill with soil, firming gently around the base to remove air pockets and ensure good soil-to-root contact. The planting depth should be such that the crown of the plant (where the roots meet the stem) is at soil level.
Potted perennials are generally easier to handle. Carefully remove the plant from its pot. If the roots are tightly bound (root-bound), gently tease them apart with your fingers or a blunt tool. This encourages them to spread out into the surrounding soil. Dig a hole that is twice the width of the pot and just as deep. Place the plant in the hole so that the top of the root ball is level with the surrounding soil. Backfill the hole with the soil you removed, incorporating some compost if needed. Water thoroughly after planting to settle the soil and eliminate air pockets.
Spacing and Arrangement
Proper spacing is crucial for the long-term health and aesthetic appeal of your perennial borders. Overcrowding can lead to competition for light, water, and nutrients, and can also increase the risk of fungal diseases due to poor air circulation. Research the mature size of each perennial before planting and space them accordingly. It's often better to plant smaller, younger plants with adequate space to grow into, rather than trying to fill gaps immediately with plants that will soon become too large. Consider the mature height and spread when arranging plants, placing taller varieties at the back of borders and shorter ones towards the front.
When planting a border, arrange plants in drifts or groups of three or five rather than single specimens for a more natural and impactful display.
Watering and Aftercare
After planting your perennials in March, water them thoroughly, even if the soil is already moist. This helps to settle the soil around the roots and ensures good contact. For the first few weeks, monitor the moisture levels regularly. While established perennials are drought-tolerant, newly planted ones need consistent moisture to establish their root systems. Water deeply rather than frequently, encouraging roots to grow downwards in search of water. Mulching around the base of the plants (but not touching the stems) with a layer of compost, bark chips, or straw can help retain soil moisture, suppress weeds, and regulate soil temperature.
The key to successful perennial planting in March is to provide a stable, moist environment for root establishment. While the weather may be variable, careful preparation and planting techniques will lay the groundwork for a flourishing garden.
Common Pitfalls to Avoid
Even with the best intentions, certain mistakes can hinder the success of planting perennials in March. Being aware of these common pitfalls can help you avoid them and ensure your garden thrives.
1. Planting in Waterlogged Soil
As mentioned, the most significant risk in March is planting into soil that is too wet. Waterlogged conditions restrict oxygen to the roots, leading to rot and a failure to establish. If the soil is heavy clay, ensure it has adequate drainage, and if necessary, amend it with grit or compost to improve its structure. Always perform the squeeze test before planting.
2. Overcrowding New Plantings
It's tempting to fill a border densely, but plants need space to grow to their mature size. Overcrowding leads to competition, poor air circulation, and can make plants more susceptible to pests and diseases. It also means you'll need to divide or move plants sooner than you might expect, which can be a disruptive process.
3. Neglecting Aftercare
Newly planted perennials require consistent attention, especially in their first few weeks. Inadequate watering is a frequent cause of failure. While they are hardy, they are not yet established. Ensure they receive adequate moisture, particularly if dry spells occur, and keep an eye out for early weed competition.
Don't underestimate the importance of soil preparation. Rushing this stage can lead to long-term problems that are harder to rectify later.
4. Choosing the Wrong Plants for the Location
Selecting perennials without considering your garden's specific conditions – sun, shade, soil type, and moisture levels – is a recipe for disappointment. A plant that thrives in one garden might struggle in another. Always match plants to their ideal environment for the best results.
5. Planting Too Deeply or Too Shallowly
Both extremes can be detrimental. Planting too deep can suffocate the crown of the plant, while planting too shallow can lead to the roots drying out and the plant being dislodged. Aim to have the top of the root ball or crown level with the surrounding soil.
By taking a mindful approach to soil preparation, plant selection, and aftercare, you can ensure that the perennials you plant in March will provide years of beauty and enjoyment.