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Plant perennials — the 5 most important tips!

Perennials are hardy plants and delight with lush splendor year after year. With the right knowledge, you will soon be able to enjoy the variety of robust plants in your own garden or on the balcony. There are perennials for a wide variety of locations, they are perennial, bloom reliably and remain outdoors during the cold season. In addition to the fact that perennials are hardy and planted in the ground for many years, the famous perennial gardener and plant breeder Karl Foerster noticed as early as 1925 that perennials require very little care. Almost 100 years ago he wrote an article entitled «Flower Gardens for Intelligent Lazy People». Find out what this statement is all about today, because we answer questions like «When to plant perennials?»

With the right knowledge about hardy perennials to your own perennial bed

With hardy perennials you can give your garden and balcony a very personal touch. In combination with shrubs, bulb plants and annual plants, perennials are guaranteed to become your favourites. The herbaceous and perennial plants sprout year after year and please with lush flowers or decorative foliage. Before planting, take enough time to prepare the soil, get to know the different growth forms, the different perennial species and varieties. The large selection of perennials (hardy), flowers and other suitable companions leaves nothing to be desired and gives you an insight into which perennial plants are ideal for you .In this article you will learn how and when to plant perennials and what needs to be considered when caring for hardy perennials.

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1. When to plant perennials? The best planting time


When to plant perennials you ask yourself? The best planting times for all perennial species are in autumn and spring. Here your new plantings can quickly gain a foothold in the ground, because reduced length growth makes it easier for the perennials to take root. The same applies if you plant berry bushes, hedge plants or fruit trees. In principle, however, perennials can be planted in pots all year round. If you want to plant the herbaceous plants in summer, all you need is a little more finesse when watering.

Exception: Pampas grass is a hardy plant, but you should give the ornamental grass some shelter during the first winter. Read in our plant encyclopedia how best to overwinter the grass. Cotaderia must also be well rooted to survive the cold season. The ideal planting time for pampas grass is March to August.

2. Preparations before planting perennials

The choice of location is essential for lush perennial splendor. If you have a shady garden, so-called “shade perennials”, i.e. perennials for shady locations, are suitable. Perennials for partial shade are also suitable for some locations. In full sun, the group of sun shrubs is in demand. Only if the location is taken into account will you have great pleasure with these hardy plants.

Loosen up the bed well before planting. Remove all weeds from the perennial bed. Above all, you must collect all plant parts and root pieces from the soil of the root weeds groundweed and bindweed. If this care measure is not taken, the new perennials cannot develop so well and the weeds always remain in competition with the cultivated plant. Depending on what demands the selected plant has on the soil conditions, put high-quality balcony soil or a mixture of plant soil and sand in the planting hole.The latter is particularly important for rock garden perennials, succulents and alpine perennials, as these are sensitive to waterlogging. The right location is the guarantee for success for the individual plants.

3. Planting instructions for hardy perennials


Once you have found the right species, you can start planting:


First, dig a planting hole. This is ideally twice as wide and deep as the plastic pot that your hardy perennials are in. Before planting, the root ball should be well moist. You can also cut off the above-ground parts of the plant a hand’s breadth above the pot, because initially rooting is more important than growth and flowering.

Our gardening tip: place the plant in a bucket filled with water for a few minutes. As soon as no more air bubbles rise, the plant can be taken out of the bucket and potted out.


Providing your hardy perennials with nutrients is important to get them off to a good start. These should be administered in the form of slow-acting fertilizer. Either you prepare your bed with Kölle’s Beste perennial fertilizer or you put Kölle Bio Root Power in the planting hole when planting.

When planting, note the distance between the plants. Depending on the species, the planting distance between the plants is 10 to 20 cm. Solitary plants are planted at intervals of up to 40 cm. You can fill the gaps between the hardy perennials with annual summer flowers in the first and second year. As soon as the large perennials have established themselves in the soil, they develop their final size and intermediate planting is no longer necessary.

Press the perennial firmly with your hands. In this way you create a good soil contact and the plant takes root quickly.

Immediately after planting , water each perennial with 2 to 3 liters of water. This promotes the connection between the plant and the soil.

To avoid unwanted weeds, you can cover the freshly planted perennials with some mulch or compost. Grass is unsuitable because mold would form. Mulching also reduces evaporation. The compost is best applied before winter. This gives you hardy flowering perennials that are healthy and robust.

Water as needed over the next few weeks. The main factors here are solar radiation and precipitation. Until the hardy plants are rooted, it is important that they are watered as needed. The right time to water is early morning. Ferns in particular, like hydrangeas and rhododendrons, should not be watered in the blazing midday heat. A burning of the green would be the result. Make sure you give the water directly to the roots and do not wet the aerial parts. This is the most effective method of minimizing fungal diseases, especially with phlox (insults) and delphinium (larkspur). Hardy perennials will thank you!

4. Perennials in the garden – this is how a perennial garden is conjured up


Once your perennials have established themselves in the garden, it is a pleasure to see how robust and easy to care for the beauties are. Wonderful additions are annuals that are not hardy or bulbous plants. If you fill the gaps between the perennials with dahlias in the first year, you can quickly and easily achieve extensive planting. After just 2 to 3 years, most perennial plants will completely cover the area and unwanted weed growth will be suppressed. Another option is ground cover. These flat-growing plants are often evergreen and cover the ground by forming stolons. bloomingcushion phlox, stonecrop, rockrose and many other plants are decorative and practical at the same time. If you cut this ground cover immediately after flowering, the second flowering may be weaker. A pruning in the spring damages the flower base of the early-flowering varieties. Therefore, care should be carried out in the same way as rock garden care. Ground covers such as cranesbill, which sprout in spring, can be pruned after winter.

You never have to cut some perennials. These include peonies, bleeding heart or lily of the valley. The green of these genera assimilates over months and stores energy in the tubers for the coming season. Only remove the dry leaves before the next shoot. The storage organs of these perennials are hardy and can remain in the ground all year round.

With perennials for dry locations, it is important that you water them from time to time in phases without precipitation. Basically, the effort with perennial plants is not high compared to balcony plants. Native perennials in particular can cope very well with the climatic conditions in your perennial garden. Another advantage of the native species is that they are a valuable food source. With plenty of pollen and nectar, they serve as forage plants for butterflies, bees and other insects for a long time. Learn more about this in the Insect Perennials section.

5. Perennials in pots


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Don’t have a garden and still want to take advantage of perennial planting? Perennials also cut a fine figure on the balcony and terrace. With a sufficiently large planter and the appropriate knowledge about planting , many perennials also feel at home in tubs and large pots. Like trees and shrubs, flowering perennials can function as container plants at any time of the year. It is important that the perennial plants are pruned after flowering and cared for according to their respective needs. Lavenders grow best in a sunny location and delight with a long flowering period. Hostas or ferns are suitable as tub plants for partially shaded areas. Our tub garden consultant will tell you what is important when planting in tubs. With our professional tips, nothing can go wrong when planting perennials. The advantage is that perennials are hardy, robust and attractive.

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