10 fast-growing perennials for quickly filled beds

Many amateur gardeners will recognise the sight of bare soil between newly planted specimens. The wait can feel endless, weeds seize every open patch and the border simply looks empty. Carefully chosen, fast-growing perennials can shorten this period considerably: they fill beds quickly, flower for a long time and provide insects with a lavish buffet.

Why fast-growing perennials are a game changer in the garden

Perennials return from the same root system every year, saving a great deal of work compared with annuals. Choosing varieties that establish rapidly brings two advantages: the garden looks full and lively sooner, while the plants suppress weeds by quickly covering exposed soil.

“Fast-growing perennials bring structure, colour and life to the garden – permanently, not just for one season.”

There is also a nature-conservation benefit. Many of these plants are classic insect magnets, supplying nectar and pollen to solitary bees, honey bees, bumblebees and butterflies, often for many weeks. A garden rich in flowers is not only attractive; it also hums and flutters with life.

Most perennials follow a similar establishment pattern: they settle their roots in the first year, put on noticeably more growth in the second, and often form mature clumps by the third. The species described here speed up this process significantly, provided their position and care are suitable.

Position, light and soil: helping perennials grow strongly

Light determines whether these plants truly thrive. Full sun means around six hours or more of direct sunlight each day, while partial shade is roughly half that amount. Put a sun-loving perennial in shade and, instead of flowers and vigorous growth, you will get disappointment and weak shoots.

Nearly all fast-growing perennials prefer free-draining soil. Waterlogging causes roots to rot, particularly over winter. It is therefore worth preparing the ground before planting:

• Loosen the soil and remove stones and old root material.
• Dig out weeds thoroughly rather than merely cutting them back.
• Work in sand or horticultural grit where the soil is heavy.
• Mix in well-rotted compost to provide nutrients.

Starting with well-rooted plants in pots rather than tiny young plants will produce a closed planting scheme more quickly. During the first season, water regularly until the perennials have anchored their root systems deeply in the soil.

10 turbo perennials for quickly filled beds

1. Agastache – fragrant flower spikes for sun and insects

Agastache, often called giant hyssop, produces upright flower spikes in purple, pink or orange throughout the summer. It soon develops into compact clumps and performs especially well in full sun. The foliage has an aromatic scent, while bees and butterflies visit constantly.

2. Catmint (Nepeta) – blue flower cushions with few demands

Catmint rapidly forms broad, low mounds covered in blue or violet flowers. It works well at the front of borders, beside paths or in front of roses. Maintenance is minimal: cutting it back after the first flush of flowers often encourages a second wave of bloom.

3. Tickseed (Coreopsis) – yellow sunbursts well into autumn

Tickseed produces vivid yellow or bicoloured flowers that sit like tiny suns above the foliage. It grows quickly yet remains airy, never appearing cumbersome. It flowers especially reliably in free-draining, relatively lean soil.

4. Blanket flower (Gaillardia) – fiery colour for hot spots

With its red, orange and yellow blooms, blanket flower creates bold colour accents. Once established, it copes well with heat and drought. Removing faded flowers regularly extends its flowering season into autumn.

5. Gaura lindheimeri – floating flower clouds in the summer breeze

Gaura lindheimeri carries countless small, delicate flowers on long, flexible stems. Borders take on a lighter, more playful appearance in a short time when it is included. It is ideal for naturalistic planting schemes and combines beautifully with grasses.

6. Red hot poker (Kniphofia) – exotic torches for a focal point

Red hot poker produces strong flower stems that stand in the border like colourful torches in orange, red or yellow. It quickly makes an impact in sunny, free-draining ground and is an excellent focal point in mixed perennial borders.

7. Cranesbill (hardy geraniums) – a living ground cover with lasting impact

Hardy geraniums quickly spread into dense carpets. They conceal bare soil, keep weeds under control and flower in pink, blue or violet, depending on the variety. Some types bloom only in early summer, while others continue for months.

“Anyone looking for a lively, low-maintenance ground cover will almost always make a good choice with cranesbill.”

8. Perennial sage – repeated displays of violet flower spikes

Perennial sage produces successive rows of upright flower spikes during the season, usually in rich violet or blue shades. Cutting it back after the main flowering period stimulates a second display. Bees love its abundant nectar, and sage gives a perennial border a sense of order and structure.

9. Daylily – robust flowering clumps with addictive appeal

Daylilies quickly build impressive clumps. Each individual flower lasts only one day, but new blooms continually replace the old ones. Colours range from soft cream to deep dark red. The foliage remains attractive for a long period and reliably fills gaps in the border.

10. Bee balm (Monarda) – aromatic flower heads for bumblebees and more

Monarda forms rounded, striking flower heads in red, pink or purple. It spreads through short runners, gradually occupying more space. Its leaves smell of bergamot or mint, and bumblebees descend on the flowers in great numbers.

How to help perennials knit together even faster

Thoughtful spacing speeds up the process of covering an area. Plant too far apart and you will be looking at bare earth for a long time; plant too closely and division will be needed after only a few years. These guidelines allow quick yet healthy growth:

Perennial	Recommended spacing	Plants per m²
Catmint, tickseed	30–35 cm	8–10
Cranesbill, perennial sage	35–40 cm	6–8
Daylily, red hot poker	40–50 cm	4–6
Monarda, Agastache	40 cm	6–7

An organic mulch of composted bark, woodchip or leaves reduces evaporation, keeps the soil moist for longer and makes it harder for weeds to establish. This protection makes a major difference to the rate of growth, especially in the first year.

Sunny, dry or moist: suitable combinations

Some of the plants listed favour heat and dry soil, while others prefer a slightly moist part of the garden. The best choices for dry, sunny positions are:

• Agastache
• Catmint
• Tickseed
• Blanket flower
• Gaura lindheimeri
• Red hot poker (with drainage)

Monarda and many cranesbill varieties, by contrast, appreciate somewhat fresher soil. Daylilies cope with both conditions, as long as water does not remain standing permanently. When planning mixed planting, place varieties with similar needs together so that no species suffers over time.

What else gardeners should keep in mind

Some of these perennials can be so vigorous that they overwhelm weaker neighbours. Monarda and certain cranesbill varieties, in particular, spread strongly. To keep them in check, plant them with root barriers or divide the clumps every few years using a spade.

Perennials make a greater impact when planted in groups rather than individually. Just three to five plants of the same species will already create a harmonious picture. Repeating catmint, perennial sage and tickseed through a border, for instance, produces a closed, colour-coordinated area with clear structure within a single season.

These plants are also practical for people with limited time. Once established, they generally need only cutting back, occasional division and a little compost from time to time. The reward is a garden that remains densely planted from spring until autumn and looks far more labour-intensive than it really is.