Enjoy more flowering trees

AS ALL allergy sufferers will have noticed, the prosopis are producing very bright green new leaves and are coming into flower.

Usually multi-stemmed, with stems curving outwards from the base, these trees remind me of a bunch of bright green ostrich feathers.

Their pale yellow, fairly long, hanging flower spikes are arranged all along the branches in contrast to those of the acacias that are usually borne on the outside of the tree.

In addition to causing heavy aller- gies the prosopis is highly invasive particularly in the dry riverbeds of the southern half of Namibia, where it almost entirely displaces the indigenous vegetation and spreads into the adjacent countryside.

Originating from Mexico where it is known as “mesquite”, there are several prosopis species which are difficult to distinguish and most of which came into our country accidentally with horse fodder.

They hybridise and have become very invasive.

Only one species, Prosopis africana, usually a single-stemmed tree with very fine leaflets and without any thorns, is indigenous to North Africa and not invasive.

This tree was originally introduced to the southern parts of Namibia for shade, fuel and fodder, since the numerous pods are very nutritious.

The wood of all prosopis species is very good fire wood and it is also very durable. Nevertheless young prosopis should be eradicated wherever possible, while mature trees should be harvested for their useful wood.

Another common cause of allergies during this time of the year are the lovely blue flowers of the jacaranda () originating from Brazil, now very visible in many gardens and along many streets in Windhoek.

In water-rich areas such as the gorges of the Waterberg they may become naturalised and spread into the surrounding bush. If you take a walk in the National Botanical Garden in Windhoek, in the surrounding hills or in other mountainous environments in northern Namibia, you may see the skew-leaved elephant root () in flower [photo].

The long, golden yellow flower spikes appear on the reddish brown branches before the leaves and develop into very broad beans. Its large feathery leaves look surprisingly similar to those of the jacaranda. The large underground root to which the common and the botanical names refer was used for tanning.

The elephant root can make a frost and drought resistant garden plant.

The river bush willow (), A. vaderlandswilg, is found in many gardens, along pavements in Windhoek and on the parking lots of two supermarkets in Klein Windhoek. Like many Combretum species, this

tree produces short cream coloured flower spikes together with the new leaves.

The river bush willow in Namibia occurs naturally only along the banks of the Orange River, where it forms dense thickets looking more like bamboo than like trees.

The kudubush (), occurring widespread on rocky hillslopes and stony ground in Namibia has similar flowers, also becoming visible now and spreading a lovely delicate scent.

A number of different combretum species grow in northern Namibia. All of them bear 4, or sometimes 5 winged fruits of various sizes, which make them easy to identify.

Lovely white or pinkish and frilly trumpet-shaped flowers now start opening on the black branches of the trumpet-thorn (Catophractes alexandri) A. gabbabos, D Schwarz- dornsilberbusch with silvery leaves and occurring widespread all over the country.