Weeds: the ramifications if you do not remove them quickly
Weeds are species of plants growing in the wrong place. This applies to a tree, shrub, palm or other species of plant — if it is in the wrong place, remove it before it becomes a problem.
It may not appear obvious but weeds often grow quicker than “garden plants” and by so doing, they take moisture from the soil as well as nutrients.
A tree’s root zone will extend quicker than the surrounding plants with the effect that neighbouring plants do not grow to their potential height. Weeds are also notorious for being the primary host for pests, which are easily transmitted to surrounding garden material. This is also the case with fungal problems, which are easily transmitted to the detriment of their neighbours.
With smaller perennials, and especially the jumbie bean (leucaena leucocephala), which are fast growers, flower production and resulting seed production can really become a problem; with ephemerals — plants that germinate, grow, flower and seed in a short period of time — seed distribution can be prolific.
Removal of root systems is necessary to ensure no growth occurs, otherwise the objective is totally lost when regrowth occurs from stumps left in the ground. Palms such as the Chinese fan (livistona chinensis) should have their flower stalks removed to avoid producing seed. This can be a problem with mature palms when seed is allowed to fall and not raked up.
The flower bed is not as simple an entity as it might appear. At first sight one sees soil and plants — and therein lays the unseen and unknown. Plants, of course, can harbour pests and disease. Most of the time the former is quite visible to the naked eye; the latter is perhaps not so visible but can be seen, in many cases, as a “powder” covering with a brownish appearance.
Plants are located above ground and therefore more visible. However, the “problems” lie in the profile of the soil.
It can be a primary host to fungal spores and insect eggs and also the home of literally many thousands of plant seeds which have been blown by the winds or rainwater or dropped from the fur of animals.
Working the soil while weeding exposes weeds to the surface but also initiates germination and a new crop of weeds.
When new soil is introduced to the flower bed, weed seed is imported once again. It is the same when people spread a mulch — especially from the dump. Not only are weed seeds present but the process of breaking down the mulch so it becomes humus exacerbates the problem as humus is organic and thus a growing medium when seeds settle in.
Check your flower beds for unwanted material that was not planted with a purpose in mind. Removal at time of germination will save a lot of problems down the road.
If you weed when there are no weeds, you will not have any weeds. Furthering this point, remember one year’s seeding is seven years’ weeding. Many seeds are very small and not seen with the naked eye when in the soil. It is often the case when you have a load of soil delivered that within no time new growth appears, being predominantly weeds.
Some examples of plants that readily produce seed and are possible “weeds” when they germinate include the following trees: casuarina or she-oak (casuarina equisetifolia); fiddlewood (citharexylum spinosum); golden raintree (koelreuteria paniculata); cape pittosporum (pittosporum viridiflorum); Pride of India (melia azedarach); allspice (pimenta dioica); Mexican pepper (schinus terebinthifolius); white cedar (tabebuia pallida); Kamani (calophyllum inophyllum); loquat (eriobotrya japonica); black ebony (albizia lebbeck).
The list of shrubs include Surinam cherry (Eugenia uniflora); butterfly bush (Buddleja madagascariensis); bleeding-heart (Clerodendrum); lucky nut (thevetia peruviana); orange jasmine (murraya exotica); lady of the night (brunfelsia americana).
Vines or ground covers that readily seed include morning glory (ipomoea), which is usually propagated or regrown from broken roots left in the ground and Sprenger’s asparagus (asparagus sprengeri). Both can be imported in soil or mulch.
The list of perennials likely to produce “weeds” include Mexican petunia (ruellia brittoniana) and umbrella sedge (cyperus alternifolius).