Monavale
Vlei

FLORA

Getting to know the Monavale Tree Community
Bev Reeler

Soils:
Monavale is an unusual geological site – quite unlike the red ironstones of the surrounding hills (Meyrick Park, Sentosa, Avondale Ridge). It is made up of a calcium carbonate metamorphic parent rock which has a grey appearance, and breaks down into a fine grey powder. Tthe effect on our soils is to make them rather alkaline, unlike the more acid ironstones around us.

This has resulted in relatively unusual indigenous plant communities becoming established in the area that are found nowhere else in Harare. For example, distinctive orchids and aloes are found growing on bare rock surfaces – some of which are endemic to Monavale.

Ecosystems:
Natural ecosystems have the ability to support diverse insect, bird and small mammal communities, and an inbuilt mechanism to survive drought, fire, and the various other natural disasters. At the moment these ‘genetic islands’ are rapidly disappearing around Harare with the growth of the city and the cutting of trees around our margins for firewood and farming. With this in mind – it is essential to maintain as many pockets of undisturbed land as possible so as to ensure there is a genetic base which is large enough, and diverse enough, to maintain itself.
The increase in bird population on Monavale is almost certainly a result of the stands of indigenous trees still growing in our area.
Presently there are still the remnants of wild life here – night apes, mongoose, guinea fowl, one or two small buck living around the vlei margins and a snake population that is unfortunately rapidly disappearing.

Settlement
The settlements growing on the hill have obviously changed this unique area and certainly the establishment of houses and gardens over the entire hill have made a huge dent in the natural habitat. Read More

This habitation has also increased the water input on the hill, and garden watering and domestic house run-off have enabled increase in the biomass. This has certainly added to the beauty of the hill but has undoubtedly jeopardized the survival of the natural ecosystem indigenous to the area.

Many of us have sections in our garden which we have left to nature, but even these become invaded by weeds, plants and trees that we have introduced over the last 80 years. Jacaranda, Deadly Nightshade, Lantana, Gums, Sisal and Prickly Pear being the most common.

The problems with these introduced plants can be seen as they rapidly begin to invade the natural bush, and as there is nothing within our natural system which controls their growth, they begin to out-compete the indigenous trees and grasses. A number of the trees (gums in particular) have an added problem in that they change the soil around them, which inhibits other plants from germinating and growing.

Firewood
There has been an increased demand for firewood on the hill – both as a result of electricity power cuts and the increased human population on the hill. As both of these issues are likely to persist, it seems appropriate to consider the firewood management options for Monavale. This could include deliberate planting of trees for firewood as well as selective cutting of non-indigenous species.

For obvious reasons, the first trees that should be sacrificed are the Jacarandas, Firs and Gum trees that are invading natural parts of our gardens. All of these trees provide good fire wood.

However – when we begin cutting trees, it is imperative that we begin to plant replacements to ensure that the ecosystem does not become depleted.

There are a number of indigenous trees that can be planted – some of which grow fairly fast, and some of them more slowly. Both are needed. Unfortunately, Acacia gerrardii which is the dominant Acacia of the plant community seems to grow very slowly, whilst others which are less common (particularly Acacia polyacantha, and Acacia galpinii) are much faster growing. We are presently testing these for firewood, and though undoubtedly not as good as Jacaranda, they seem to suffice. A polyacantha can grow to a substantial tree within 6 years or so.

A number of large trees make up the predominate group of trees growing on Monavale. One of the ways to get to know the tree community in your garden is to start with the ones that you know or recognize already.

Acacia gerrardii / Grey haired acacia (there appears to be no specific Shona name)
This Acacia is indigeneous to Monavale, but not commonly found anywhere in the surrounding area. It has sickle shaped pods and flowers in white balls in October/November. In many gardens, the older gerrardii are beginning to die. Like all acacias, they are not particularly long lived trees, but because of their unique position in this tree community, is important to allow the young trees to survive – there are small gerrardii naturally springing back in areas which are not too disturbed.

Brachystegia boehmii / Prince of Wales Feather / Mufuti
Most residents of Monavale know these beautiful trees which are related to the Masasa. The new leaves flush slightly later than the Masasa, with the same beautiful array of autumnal colours. They are unfortunately relatively hard to grow from seed, and any young trees found growing in your gardens should be protected from fires and slashing.

Brachystegia speciformis / Masasa / Masasa
This tree needs no introduction, and is one of the most common trees of the Monavale ecosystem. Unfortunately, this too, is a hard tree to grow from seed. Young masasa can be found, both growing from seed, and springing out of damaged or roots of older trees, in untouched areas and once again, these need to be protected as much as possible. As most people on Monavale have noticed, the seed-making cycle of masasa is highly variable. Some years there is a literal explosion of popping pods that lasts for weeks, and in other years, there are almost none. Has any one any suggestions for this variation? The first orange flush of new leaves happens in early August – however, this too is a variable, with the first trees flushing as early as 10th of July this year.

Julbinardia globiflora / Monondo / Munondo
This tree is often mistaken for the Masasa, but can be told apart in various ways: The pods, though shaped like those of the Masasa, are a darker velvety brown and are carried above the crown of the tree. The leaves of the Monondo usually have 6 pairs of leaflets with the longest being the 3rd or 4th pair. The Masasa usually has 4 pairs of leaflets, with the terminal ones being the longest. The Monondo has creamy flowers from January to May, whilst the Masasa has less conspicuous flowers appearing as early as August.

Lucky Bean Trees: There are two species found on Monavale:
Erythrina abyssinica / Red hot poker tree / Mutiti
Erythrina latissima / Broad leaved erythrina / Mutiti
Both flower in late July/early August and can be told apart by the fact that the latissima has larger flowers and leaves (flower petals up to 5cm long and leaves up to 30cm in size). The pod on the latissima is similarly longer- 30 cm – whereas the pod of the abyssinica is about 10cm in length.

Combretum molle / Velvet leaved combretum / Mugodo
This is a beautiful tree with arching branches often making wonderful shapes. The leaves are covered in silvery velvet hairs and the tree produces small 4-winged fruit as early as January, which remain on the tree for many months.

Figs: Two species are found growing on the hill:
Ficus natalensis (thonningii) / Wild fig / Mushavi.
The most common one is the Wild fig which grows all over Monavale. These trees are unique because of the ability of different individual trees to produce fruit at different times of the year. This asynchronous pattern results in an almost continual supply of fruit all the year round. This tree is an enormous attractant for birds, as anyone will have witnessed, when a wide variety of fruit eaters fill the trees as soon as they begin to bear. This tree has smallish leaves seldom longer than 8cm, and small fruits which grow along the branches.
Ficus capensis (sur) / Cape fig / Mukuyu
The Cape fig has much larger fruits (up to 4cm) which grow in heavy clusters on the trunk and lower main branches. Its leaves are also larger than those of the Wild fig (up to 23cm in length)

Lannea discolour / Live long / Mbvumbu
The Lannea is a common, if inconspicuous tree, found in the Monavale plant community

Orchids Field Survey 2006

Habenaria shimperiana A. Rich.
Habenaria rautaneniana Kraenzi.
Eulophia tanganyikensis Rolfe

Monavale Vlei: List of Sedges, Legumes, and Forbs – Field Survey 2005

Rocky Fringes of Vlei
Sedges
Cyperus esculentus

Legumes
Rhyncosia spp
Sesbania spp
Chymocrysta spp
Desmodium spp
+ 2 unidentified

Forbs
Hibiscus ovalifolius
Hibiscus articulatus
Xerophyta villosa
Euphorbia dibilispina
Combretum platypetalum
Tylosema fassoglensis
Eriosema englerianum
Commelina spp. violet
Commelina spp giant
Commelina spp yellow
Commelina spp peach
Justica spp
Leptactina benguelensis
Leonotis nepetifolia
Compositae spp
Vernonia spp
Cosmos
+ 7 unidentified species
Forbs Mid vlei
Astripomoea malvacea
Nidorella resedifolia
?

Weeds occuring on raised ground
Ageratum conysoides
Nicandra physalodes
Tithonia rotundifolia
Amaranthus hyridus

Legumes
Sesbania spp.
Mid Vlei
Legumes
Aeschynomene spp

Forbs
Astripomoea malvacea
Nidorella resedifolia

Standing Water
Legumes
Sesbania spp

Wetlands – temporary water

Sedges
Cyperus esculentus
Wetlands – raised ground

Forbs
Commelina spp
Compositae spp.
Crinum macowanii
Crinum paludosum
Hibiscus dongolensis
Ipomeas spp x 4
Leonotis ocymfolis
Oldenlandia herbacea
Scabiosa columbaria
Vernonia spp
Triciceras longipedunculatum

Sedges
Cyperus spp x 2
Legumes:
Sesbania spp
Ocraluca spp x 2

Monavale Vlei and immediate surrounds. Flora list. Mark Hyde October 2010.

List incomplete but ongoing. Some overlap with other lists.

Combretum platy oatesii
Sphaeranthus flexuosus
Blumea axillaris
Nidorella resedifolia
Mimulus gracilis
Pterocarpus rotundifolius rot
Lannea edulis
Hygrophila pilosa
Scabiosa columbaria
Cycnium tubulosum
Persicaria limbata
Combretum molle
Vernonia glabra
Aerva leucura
Aristida junciformis subsp. macilenta
Vernonia oligocephala
Vigna frutescens
Ziiphus zeyheriana
Rhynchosia minima
Melinis repens
Ipomoea obscura
Aeschynomene mimosifolia
Eriosema englerianum
Ocimum obovatum
Acalypha caperonioides
Fraxinus
Arundo donax
Bauhinia variegata
Rorippa nasturtium-aquaticum
Sesbania punicea
Lantana camara
Ageratum houstonianum
Ageratina adenophora
Psidium guajava
Cyperus flabellifolius
Plantago major
Diospyros lycioides sericea
Populus canescens
Ipomoea cairica
Acacia sieberiana
Senecio randii
Acacia polyacantha
Oenothera rosea
Sesbania punicea
Ricinus communis
Gladiolus melleri
Bauhinia variegata
Alysicarpus zeyheri
Typha capensis
Pulicaria scabra
Hygrophila rhodesiana
Gazania krebsiana
Hibiscus aethiopicus
Launaea rariflora
Malvastrum coromandelianum
Physalis peruviana
Ocimum obovatum
Phoenix reclinata
Rorippa nasturtium-aquaticum
Lactuca inermis
Ziziphus zeyheriana
Nesaea heptamera
Geigeria filifolia
Vahlia capensis
Verbena officinalis subsp. africana
Diplorhynchus condylocarpon
Azanza garckeana
Combretum molle
Ocimum angustifolium
Combretum hereroense
Jacaranda mimosifolia
Acacia amythethophylla
Albuca melleri
Philenoptera violacea
Lactuca serriola
Terminalia stenostachya
Piliostigma thonningii
Pseudolachnostylis maprouneifolia
Lannea discolor
Acalypha villicaulis
Lotononis listii
Margaretta rosea
Rhus tenuinervis
Senna sungueana
Brachstegia boehmii