Bignonia

Bignonia

The Bignonia

Many plants of the genus Bignonia have been, in the last decades, united in another genus, the genus Campsis; in particular, all the bignonie that are commonly grown in Italy now belong to this genus. The most widespread species, also present in the gardens of our grandmothers, is campsis radicans, a species of American origin, with large orange flowers, and particular aerial roots, which allow the plant to attach itself to any surface; in addition to campsis radicans, we find in Italian nurseries and gardens, also Campsis grandiflora, native to Japan and Asia, which instead, to be cultivated as a climber, needs to be fixed to the stakes, and therefore is often grown in pots or as shrub; also widespread Campsis radicans var. flava, with yellow flowers, and Campsis x tagliabuana, a variety with very large, almost red flowers.

In general, these are vigorous and luxuriant climbing plants, resistant to cold, with pinnate leaves, consisting of lanceolate leaflets, with a serrated margin, light green, deciduous. From the beginning of summer, until autumn, the campsis produce large trumpet flowers, in shades of orange, gathered in large clusters, which contain from six to ten or twelve large flowers. It is a plant of easy cultivation, which has met and is enjoying great success; in the last decades some varieties have been selected, with very large flowers, or even with flowers of a decidedly very bright color, almost flaming red.


Cultivating the Bignonia

This climber is grown outdoors, in pots or in the ground; during the winter it is in complete vegetative rest, and loses its foliage, for this reason it tolerates cold and frost very well, and does not need protection; some varieties or species, such as Campsis grandiflora, can fear very intense frost, and should therefore be planted in areas sheltered from the wind, if we live in a place where winter temperatures are often below -10 ° C. They are vigorous plants, which tend to produce many basal suckers, and an annual growth that reaches even a few meters in length, so they are positioned in an area where it is possible to let them develop freely, such as near a pergola or a gazebo. They are grown in the ground, or in large pots, in a good porous and very well drained, light soil, even if they can bear to live in any substratum, even in the common garden soil; at the time of planting, the soil is enriched with little manure, or with slow release fertilizer; during the following years the fertilizer of potted plants is generally fertilized, while in general it is not necessary to carry out this operation for plants grown in the ground, unless they are in a decidedly very poor in nutrients, or stony soil.

Watering is provided at the time of planting; later, the adult specimens can be satisfied with the water provided by the rains, but newly planted plants may need watering in the summer, especially during flowering or in particularly dry and rainless periods. They do not like water stagnation, and excess water in the soil, so they are watered only in summer, and only when strictly necessary. Clearly, the specimens grown in pots should be watered regularly, whenever the soil is decidedly dry, avoiding excesses, and avoiding leaving stagnant water in the saucer.

Pruning is done at the end of winter, removing all damaged or particularly thin branches; in general, strong pruning tends to reduce the number of flowers produced, therefore they are practiced only when the plant is very large, or particularly damaged by the winter climate. At the end of summer, when the plant no longer produces any flowers, it is useful to shorten all the branches at the apex, to give the plant a more compact and contained habit.


Multiply the Bignonia

These plants root very easily by cuttings, taking the semi-woody apexes of the branches that do not bear flowers, in summer or at the end of spring; the twigs should be divided into portions of about 10 c in length; the leaves are detached in the lower part and the lower part of the branch is cut in oblique motion, so that the cutting surface is as wide as possible. Then the lower part of the cutting is immersed in the rooting hormone, and then buried in a compound consisting of peat and sand in equal parts, which must be kept moist until the cuttings show signs of having rooted, producing sprouts. The young plants thus obtained will have a flowering identical to that of the mother plant; they must be kept in a sheltered place, with temperatures not below 5 ° C, until they are large enough to be planted in the garden.

The flowers are followed by small fruit, which bear some seeds, generally fertile; plants obtained from seed, however, will certainly not be identical to the mother plant, if it is a hybrid; so if we see a bignonia with very particular flowers, it is convenient to ask to be able to take some cutting, rather than collect the seeds. They are sown in autumn, in pots which are then left outdoors, but in a place that is fairly sheltered from the cold; they will germinate in spring.


Trumpet flowers

The corolla of the bignonie it has a particular shape, much appreciated; the five petals are welded to the base, to form a sort of thin cone; at the apex, on the other hand, the petals widen, forming a sort of wide labellum, these lobes give rise to what we could call a kind of trumpet. In nature there are many flowers with this shape, or a similar shape. The size and color of holes of this type make them very much appreciated. The most common trumpet flowers are certainly surfinias and petunias, with their flowers of the most varied colors, from white to yellow, from pink to deep blue, which sometimes seem to be made of velvet.

The largest trumpets are perhaps those of the brugmansia and datura, which attract us for their decidedly large dimensions. Even convolvulaceae often produce trumpet-shaped flowers, with the apex of the petals still welded together, without lobes; the convolvolus cneorum has white flowers, but the thousand varieties of morning glory cheer us with flowers of all colors, and of large size. Oleander flowers also have this hole, but the tubular base is definitely much shorter than that of the bignonie; also the glossinias (sinningia speciosa) have a particular shape with a wide and enlarged “tube” and fringed lobes, the color is always very bright, for a very pleasant effect.

And the list could go on and on: catalpa, paulonia, weigelia, kolkwitzia, Jacaranda, Bouvardia, Pentas, Gelsomini.

Few people know that asteraceae also have tubular flowers, that is, made up of a thin and small tube; the flowers of asters, daisies, sunflowers, are gathered in inflorescences called flower heads, which can count up to thousands of flowers; the true flowers are those that we can observe in the central disk of the inflorescence, and are arranged side by side, closely attached; the flowers placed in the external area of ​​the inflorescence have one or a few petals, forming what we often think is the corolla of the flower, these particular petals, very large compared to the flower, are called ligules, and are characteristic of asteraceae.