Delphinium: Planting, Maintaining & Propagating

The delphinium is one of the absolute classics in the garden. Here you will find out everything you should know about planting and caring for this popular perennial.

The delphinium (Delphinium) enriches every garden with its wonderful colors and its botanical name already suggests that the flowers of the delphinium resemble a dolphin. The tall ornamental plants are an integral part of many gardens - we explain what else you should know about these beautiful plants.

The delphinium belongs to the buttercup family (Ranunculaceae) and is one of the most famous and certainly most beautiful perennials that we can put in our gardens. But what maybe not everyone knows is that the delphinium is a poisonous plant, because that contained alkaloids (Elatin, Delphinin and others) make the plants and especially their seeds extremely poisonous. This property even earned the delphinium the title of “poisonous plant of the year” in 2015.

Larkspur: origin and characteristics

The different delphinium species come either from the Mediterranean or from the Asian region. The delphinium has erect stems that are sometimes branched. Wonderful single or double flowers then grow on these stems - they are a striking ornament for your garden. The delphinium with its wonderful flowers is also ideal as a cut flower or for drying. Larkspurs are available in the flower colors white, pink, red, blue and purple. These flower colors are of course available in a wide variety of color gradations and the flowering of the knight spurs can be admired from June to August.

Larkspurs can vary greatly in size, as the smallest species only reach a height of about 20 centimeters. However, some larkspurs manage to grow to a height of two meters. Such an ornamental plant looks great in the garden, of course, but it also requires additional maintenance - such tall plants are always at risk of tipping over, especially in strong winds. You also have to be careful with the delphinium's bed neighbors, because not every plant is suitable for it. Bluebells are suitable as neighbors for the delphinium (Campanula lactiflora), Irises (Iris barbata), Daisies (Chrysanthemum maximum), Cranesbill (Geranium) or yarrow (Achillea filipendulina). The irises are even said to promote the growth of the delphinium. On the other hand, one should avoid flaming flowers (phlox) and asters (aster) near the delphinium, as the roots of these plants do not understand each other and cause damage underground.

Delphinium species

There are many different types of delphinium, differing in size, color and where they come from. In total, there are an estimated 400 different delphinium species, most of which come from different parts of Europe. The lark spurs can be subdivided botanically or according to the crossing types or hybrid varieties.

Delphinium: Botanical Differentiation

• Garden barnacle or hyacinth barnacle (Consolida ajacis)
• Field barber's spur or field barber's spur (Consolida regalis)
• Dwarf larkspur (Delphinium grandiflorum)

As you can see from the different species names, the system is in the genus of Larkspurs are very complicated and some of the species names have also changed in recent years changed. Such modifications come about through more precise analytical methods, since molecular biology today gives rise to relationships can determine more precisely among different plants than in the past, where the systematics is established solely through the appearance of the plants became.

In breeding circles, a distinction is made between the following delphinium species or delphinium hybrids:

• Elatum group (tall garden knight's spur)
• Pacific group (Pacific garden barnacle)
• Belladonna group (half-height delphinium)

The wild larkspurs are usually only annual or biennial, whereas cultivated garden forms are often more durable. It is generally said that the higher a delphinium, the longer it lives. For example, the Pacific varieties can only live up to three years, Belladonna varieties can live up to five years and Elatum varieties even manage to reach an age of ten years.

Buy delphinium: you should pay attention to that

If you are in the nursery and want to get a new delphinium plant, there are a few small things you should consider in order to take an optimal plant home with you. So you should keep your hands off larkspurs, which are already in full bloom in the nursery, because these plants will grow very poorly in your garden. It is of course very tempting to buy such a beautiful flowering delphinium plant, but you will not get much pleasure from it. Otherwise you should of course - as with all purchased plants - also pay attention to the health of the plants, because after all you don't want to bring diseases and pests into your garden. It is therefore important that you make sure that there is no fungus coating on the leaves. You should also check the plants for pests. The eggs are often found on the underside of the leaves or you can see traces of eating on the leaves. Always check each plant for damage, leaf discoloration, or other symptoms before buying.

Of course, when it comes to buying larkspurs, we cannot avoid Karl Foerster, who was a well-known gardener and perennial grower and who bred countless wonderful larkspurs. Karl Foerster died in 1970, but his breeds survived him and of course you can buy them in many nurseries, including Foerster-Stauden in Potsdam-Bornim.

Plant delphinium

Lark spurs need a lot of nutrients and therefore you have to convert them again and again so that the soil is not excessively depleted. In the following you will find a few points that you should consider when planting larkspurs so that you can enjoy the beautiful ornamental plants for a long time.

The perfect location for delphiniums

In order for the delphinium to grow optimally, it needs a sunny place in your garden, where it is protected from the wind. The delphinium does not want to stand in the blazing sun, because it prefers the sun on the head and shade on the feet, as the saying goes. It is therefore advisable to place other low-growing ornamental plants around the delphinium that can provide shade. The delphinium prefers a loamy-humus soil, which should be rich in nutrients and deep, but poor in nitrogen. In order for a sown delphinium to germinate, it needs a cool soil temperature of 10 to 12 ° C.

The correct procedure for planting delphinium

Larkspurs can be sown outdoors either in autumn until mid-October or in spring in March and April. You can also sow the larkspurs in boxes and pots indoors from the end of March and prefer them. This gives the plants a head start in growth and protects them from pests and diseases when they emerge. In addition, larkspurs that have been brought forward are also protected from frost events in this way, as these are only planted from mid-May. You should keep a planting distance of 15 to 30 centimeters.

How do you properly plant delphinium?

• Water the delphinium root ball before planting
• Dig a hole with enough space for the root ball
• Put fertilizers such as manure or compost in the planting hole
• Put the delphinium in the hole
• Make sure that the delphinium's root ball is flush with the surface of the earth
• Fill in the hole with the excavated earth
• Press the earth around the delphinium
• Water the delphinium thoroughly

Maintaining the delphinium

So that you can enjoy your delphinium all summer long, there are a few things to keep in mind when caring for these plants. Because of their height, larkspurs are very sensitive to wind, which is why they always have a sheltered place for them You should look for your delphinium, otherwise there is a risk that it kinks or blows over will. Optimal care also includes pruning the knight's spurs in summer. Once the delphinium has bloomed, you should trim the stems to eight inches. The plant will rejuvenate and sprout again. You can therefore expect a second bloom in late summer. A pruning is also recommended to prevent the delphinium from getting very high, because the higher the stems of the delphinium, the more susceptible to wind they become. Do not cut the delphinium deeper than 20 centimeters, otherwise it may not be able to sprout.

Pour delphinium

Larkspurs have to be watered sufficiently and regularly for optimal development, since the delphinium has a very high water requirement. If the weather is very hot and periods of severe drought occur, you should water the delphinium at least once a day, if not twice. To avoid excessive water evaporation, you can spread a layer of mulch around the delphinium or create shade with plants that cover the ground.

Fertilize delphinium

It is highly recommended to add some fertilizer such as compost to the soil before planting or sowing. Rotted horse manure is also particularly suitable for fertilizing larkspurs. Since the plants are shallow roots, you only need to put the fertilizer about 40 centimeters into the soil. It is advisable to fertilize perennial jousting spurs organically twice a year, whereby it is ideal to fertilize organically once in spring before budding and once in autumn after pruning. Organic remedies, such as your own, are suitable for this Compost, as a fertilizer. You can also use ours Plantura organic flower fertilizer use to provide your delphinium with enough nutrients to protect it through the winter.

Compost, manure or other organic fertilizers should always be carefully worked into the soil, being careful not to damage the roots of the plants. The advantage of organic fertilization in autumn is that the fertilizer already decomposes a little can be opened up and your plants get a strong start next spring guaranteed. If you use mineral fertilizers for your delphinium, it is advisable to always pay attention to the instructions for use and especially to the dosage. In our special article you can find out more about Mineral fertilizers.

Larkspur multiply

The delphinium sows itself when the fruit heads are allowed to fully ripen. If you are not satisfied with this individual sowing, you can also opt for another variant. Usually nowadays the delphinium is multiplied by dividing the stick.

What is the best way to split delphinium in order to multiply it?

• Dig up your delphinium
• Use a spade to divide the root ball
• Place the split root ball in a bucket full of water
• Dig a planting hole and loosen up the soil in it
• Mix compost into the hole in the ground
• Place the delphinium in the planting hole as described above

Larkspurs are divided in spring, the month of April is best. In the best case, these larkspurs will bloom in the same autumn or next spring and delight our eyes with their wonderful flowers. Of course, you can also use its seeds to multiply the delphinium, which you can then easily re-sow. To do this, you must not cut back the delphinium, you have to let it wither so that the seeds can develop. It is important not to cut back the delphinium after the first flowering so that the seeds have enough time to mature. Follicles then develop, in which there are characteristic triangular seeds. You can now collect these fruits when they have turned brown and are dry - but you have to collect them before the fruits burst open and sow themselves.

If necessary, you should dry the collected fruits. Then the seeds are to be cleaned and stored in a dry and dark place. In spring you can move the seeds forward from March or sow them directly into the ground from May. If you propagate hybrid larkspurs yourself, the following generations will have different properties and their appearance will vary from the parent plants - but this allows you to add some diversity to your garden bring.

Hibernate delphinium

Larkspurs in the open do not need any special winter protection, except that they are cut back in autumn and a further dose of compost is added. For perennial knight's spurs, this treatment is completely sufficient for them to sprout again in spring. For annual and biennial varieties, you should either have them planted yourself or collect the seeds.

However, plants that are grown in pots need shelter to get through the winter. These are more sensitive and should be protected as follows to protect against frost:

• Wrap the tubs with fleece
• Set up the buckets in a protected location, for example on the wall of a house or in corners
• Place the buckets on styrofoam or wood to keep the cold off the floor
• Cover the plants with sticks or leaves

Here you can find out more about the Hibernate different plants and about which of them can survive our winter without any problems.

Common diseases and pests in delphinium

Our delphiniums are also repeatedly threatened by various animal pests. He is particularly often from Snails (Gastropoda), Leaf miners (Agromyzidae) and holy skin mites (Tarsonemidae) infested. But some diseases also occur in the delphinium, for example blackness of bacteria (Pseudomonas delphinii), Powdery mildew (Erysiphaceae) or viruses. The occurrence of pests and diseases is often promoted by an unsuitable location - with larkspurs this is often too shady. You can use plant manure for prevention to strengthen the knight's spurs. If the delphinium is attacked by fungi like powdery mildew, then you can simply cut off the infected shoots and thus contain the infestation.