Friday, September 18, 2009

Summer is here! We have a new gardener and almost from the moment he started the garden started to flourish again. Plants are aware of people - I am certain.

Our last garden helpers planted far too many onions - but can you have too many onions? I actually don't think so!

Maxwell knows how to look after and produce large onions so we are taking his advice.

Eggplant are on the way - we have so many avocados we virtually live on them, our tomatoes are great too - avocado and tomato salad is on the menu every day - we collect about 7 a day and they keep falling out of the tree - we have to get to them before the dogs - but as we have so many why not let the dogs eat them as well!

Strawberries have been good this year already and the raspberries are starting to come up - this year we have many more shoots from the canes and our crop should be good.

The dusty berry bushes are also looking good and now with the facility to water we should get good crops of all our berries!

Thursday, September 10, 2009

The National Herbarium of Zimbabwe

The National Herbarium is an important regional herbarium housing approximately 500,000 specimens. It is the largest herbarium in the Flora Zambesiaca region and in southern Africa it ties in second place with the Compton Herbarium at Kirstenbosch, the largest herbarium being Pretoria.

The dried plant collections are subject to attack by a variety of pests and some insect damage has already occurred. Fumigation is essential at regular intervals and the latest scheduled event is now overdue.

Like most other institutions in Zimbabwe, the National Herbarium is suffering from financial difficulties at present.

In order to prevent irreparable damage to this important collection, and as the Tree Society and some of its members make use of this valuable resource, we have agreed to raise money towards covering this cost.

The (one-time) cost of the fumigation is US$ 350. Donations amounting to US$ 70 have already been received, so the outstanding amount is currently US$ 280.

Anyone wishing to donate should give such donation to the Tree Society; specifically to the Treasurer, Mr Terry Fallon (74, Lamenier Village, 4 Ridgeway North, Chisipite; tel: 481076; email: or to the Chairman, Mark Hyde (29, Harry Pichanick Drive, Alexandra Park, Harare; tel: Harare 745263; email: or to any Tree Society Committee member.

Any overseas person wishing to donate should contact me directly to discuss how this could be done.

Receipts will be issued if requested.

May I urge everyone to make a contribution, however small, to this important matter.

Please forward this email to anyone who might be interested in helping to fund this important project.

If anyone has any questions or thoughts about this, please get in touch with me.

Mark Hyde -
Chairman, Tree Society of Zimbabwe

Gardener’s guide to selecting non-invasive alien plants

Reproduced from the Tress Society of Zimbabwe - September Newsletter:

Do you want to make an environmentally responsible choice of plants for ornament, hedging, landscaping etc? Then consider the following guidelines in selecting species:
• DON’T select known alien species e.g. lantana (Lantana camara hort.).
• AVOID alien species that are similar to known invasive species—e.g. treat ALL species of alien acacias, inkberries (Cestrum spp.), cotoneasters, firethorns (Pyracantha spp.), lantanas etc. as potentially invasive. Substitution of a known invader with another plant having similar attributes will negate efforts to prevent further invasions.
• AVOID alien species that have fleshy fruits—many of the most troublesome invaders are spread by frugivorous birds, bats and other animals e.g. lantana, mulberry, guavas, privets, bugweed, syringa, prickly pears, queen of the night cactus, firethorns, cotoneasters, eglantine rose, brambles, ginger-lilies. Australian brush-cherry (Syzygium paniculatum is often sold as a ’good bird plant’ - and is on its way to becoming invasive!)
• AVOID alien aquatic species—all alien species that are climatically adapted have the potential to become invasive, e.g. sword plant (Echinodorus spp.)
• AVOID alien grasses—which are among the most invasive species in the world. Many spread prolifically from seed, underground stems (rhizomes) and runners (stolons). Fountain grass (Pennisteum setaceum), for example, is becoming increasingly invasive.
• AVOID alien climbers—which have a devastating effect by smothering the native vegetation; they are extremely difficult to control. English Ivy (Hedera helix) provides one good example. Cat’s claw (Macfadyena unguis-cati) is another.
• Avoid alien succulents—some of which have become the most costly and troublesome invasive species in the region, e.g. sour prickly pear (Opuntia stricta). Cacti are ALL alien in southern Africa (with the exception of a single small epiphytic forest species of Rhipsalis). The alien cacti are often confused with the indigenous euphorbias—don’t be fooled into purchasing a cactus that has been incorrectly labelled as euphorbia. Cacti have spines arising from specialized structures called areoles and the spines usually occur in clusters; they do not have a milky latex like the euphorbias. Agaves or American “aloes” with their tall flowering poles should not be confused with indigenous Aloe species with their showy, orange, red or yellow flowers.
Common misconceptions: cultivars and sterile plants
• Cultivars are OK because they can only be reproduced by cuttings, tissue culture etc. WRONG!—many cultivars e.g. variegated forms are able to reproduce by seed and their progeny revert to the original form, e.g. Chinese wax-leaved privet (Ligustrum lucidum) (there are two forms: normal and variegated). Queen of the night (Cereus jamacaru) has a monstrous form that sets seed which develops into the normal form.
• “Sterile” plants are OK because they do not reproduce from seed. WRONG!—some so-called “sterile” plants, e.g. pure yellow–and pure white-flowered, bushy lantana (Lantana camara hort.) produce fertile pollen that can cross-pollinate the normal fertile plants, as well as fertile embryo sacs that occasionally produce seed.
• The creeping, yellow Lantana cultivar Sundancer is marketed as “Lantana montevidensis”, “sterile” and “non-invasive”, however studies in South Africa and Australia indicate that it is partly L. camara, only sterile if planted in isolation, and inter-fertile with L. camara. Research in America indicates that a very similar cultivar, Goldrush, is probably a hybrid derived from the invasive Lantana camara complex and North American Lantana depressa. While there is no evidence that Sundancer and other yellow-flowered creeping lantanas are invasive, they are probably harmful in a much more subtle way—by swapping genes with the invasive lantana and adding the genes of L. depressa and possibly other Lantana species to the gene pool of the invasive, alien lantana complex, almost certainly increasing its genetic heterogeneity, hybrid vigour, resistance to biocontrol agents, invasiveness and suppression of indigenous biodiversity.
• Many sterile plants can reproduce vegetatively—from plant fragments e.g. jointed cactus, weeping willow, salvinia; others reproduce by suckering from the roots e.g. white and grey poplars; others from underground stems or rhizomes, e.g. giant reed, and from aerial tubers, e.g Madeira vine (Anredera cordifolia)
• Plants with only one sex present are OK because they can’t produce seed. WRONG! — purple pampas grass (Cortaderia jubata), for example, can produce seed without pollination (apomictic reproduction)

Reproduced (with minor editing) in the interests of science from SAPIA NEWS No. 10, January 2009.
Mark Hyde Home 745263
Cell 091 233751
Ruth Evans Home 331198
Terry Fallon Home 481076
J-P Felu Home 304916
Eva Keller Home 339368
Richard Oulton Home 870540
Mimi Rowe Home 882719

Tree Life Editor Home 302812

The Tree Society’s e-mail address is (Ruth Evans)

The Tree Society web site is