The long-term benefits of knowing when to weed
A weed is a plant that is considered undesirable, or simply a plant that is in the wrong place.
The adage one year’s seeding equals seven years’ weeding, has a great ring of the truth; simply observing growth these last several months leads me to think this could be a heavy year in the exercise of seed dispersal.
This is especially the case with many invasive tree species such as Chinese fan palm (livistona chinensis); pride of India (melia azedarach); jumbie bean (leucanea leucocephala); Mexican pepper (schinus terebinthifolius); whistling pine (casuarina equisetifolia); fiddlewood (citharexylum spinosum).
Kamani (calophyllum inophyllum) has been around for many years. It is a very hardy evergreen, with small white flowers and yellow stamens followed by a small round brownish seed, which germinates readily. There is, however, another species, Madagascar olive (noronhia emaerginata), which is also found island wide and is very similar in appearance.
In my neck of the woods there has been a surge of flowering of an unidentified clerodendron. This flowering, followed by a large amount of seeds will, during the coming months, develop into a mass of new seedlings as this plants flowers and seeds readily.
Plants are propagated in several ways, with cuttings and seed being the most common. They are dispersed by wind, rain, on animal coats and birds; in other words their spread is wide and far-reaching. Germination on many species is high – simply by the amounts of seed produced – as is coverage; with so many seedlings germinating in close proximity, and taking into consideration their rate of growth, consider the root activity. The end result is a mass of roots that can restrict any new plantings and seriously impact root. In such cases a tractor with heavy curved tines will be required to rip out roots; resoiling will be required for new plantings.
Many shrubs are also problematic with regard to seed production and dispersal. These include, but are not limited to, Surinam cherry (eugenia uniflora) and lucky nut (thevetia peruviana).
Weeds create a labour-intensive situation and the longer they remain in situ, the more troublesome they become. This is especially so in ephemerals, plants that germinate, grow, flower and seed in a short period of time. When left unattended and allowed to flower and seed the effect is a new crop of seedlings germinating wherever seed landed.
In such a scenario, garden owners do not always realise that weeds in their garden could well have a provenance from their neighbours’ properties. Weeds, when not removed by their roots, can and will revegetate quickly, which uses up more space as they grow requiring more soil, water and nutrients – oft to the detriment of the garden plants.
A similar problem occurs when plants are allowed to grow between paving stones or bricks as well as in dry stack walls and on rock outcrops or rock faces. In the case of dry stack walls the result can be such that to extricate the root system involves disassembling the wall followed by the task of assembly!
When root systems establish themselves on Bermuda stone rock cuts as the roots enlarge they can weaken the rock strata with rock collapse being the result.
In areas of restricted growth roots will lift paving stones – as can be seen in parts of Hamilton – which increases the incidence of possible accidents.
Tarmac driveways are also suspect to lifting and cracking when root systems do their thing and follow the easiest route to finding water.
When designing slopes and banks the degree of slope should be considered when making the plant selection. On steep slopes, plants which have low-growing spreading habit will give cover over bare soil and arrest potential erosion.
Larger plants, which have a heavy top growth, can be moved around in the wind as can the root system – roots will follow water and water runs downhill. The result is that plant roots can become duckfooted on the down slope reducing the anchoring effect of the root system on the upper slope. As such there is less resistance from strong winds when from the up slope side.
Weed or invasive trees are more than often quick to be blown over in hurricanes because of a weaker root system and the fact they are often self-seeded plants.
If it’s a weed today it will be a bigger weed in a month’s time so don’t delay remove today!
Malcolm Griffiths is a trained horticulturalist and fellow of the Chartered Institute of Horticulture in the UK. He is also past president of the Bermuda Horticultural Society, Bermuda Orchid Society and the Bermuda Botanical Society