The importance of treatment cycles - Weedingtech NZ


Spring is the time when weeds start to germinate and rise-up from the seed bed. Unseasonably hot weather can cause seeds to germinate early – causing weed growth to spiral out of control unexpectedly.

Treatment cycles are critical to ensure that weeds are tackled before they get too big. This means weeds can be brought under control for the year ahead. This stops the need to firefight to regain control of them when they have not been treated soon enough. If you manage weed control effectively from the beginning of the year, it will reduce time and cost spent on it in the longer term and help to maintain the aesthetics of the area being treated.

Variables to consider before getting started

In order to treat an area and the vegetation in the most effective way, it is important that prior to treatment, the following variables are considered to gain a holistic view of the site. This will then allow for the most appropriate treatment plan to be created.

Client requirements

These are a key factor to influence the treatment of an area as client requirements underpin the level of vegetation growth that is tolerated and will determine when the site needs to be treated and how frequently.


Air temperature, ground temperature and rain levels will all affect weed growth in an area. Warm, wet weather is likely to speed up germination and growth (but there are always some exceptions as some annuals only germinate under cool conditions, others are the opposite).

Ground cover

Understanding the ground cover in the treatment area is important as this can effect weed growth. It will also have an impact on how to treat the weed. Hard-standing will require different treatment to soft flowerbeds or deep mulch etc. Understanding the fertility of the soil will influence how fast weeds will grow.

Site use

Site use helps determine which types of weeds will grow over the site to be treated. A cultivated site for instance will encourage annual weeds. An uncultivated site is more likely to have perennial weeds.

Site history

Site history is one of the most important variables to consider. What has previously grown there and how it has been previously treated will help determine the growth of the weeds in the area. This will have an impact on the speed of treatment required for the area also. Low vegetation density will mean speed of treatment can be carried out faster than if there is highly dense vegetation present.

Time of year

This is important as it determines at which stage of growth weeds are in. It also determines the restrictions around when vegetation can be treated with regard to the weather, as some methods will be rendered invalid in unsatisfactory weather conditions. Weather, however, is not a factor which affects when Foamstream can be used as it can be used in all weathers.

Types of weed life cycle

The types of weed that grow in an area are key to understanding how to approach a site when it comes to treatment cycles.

There are four key types of weed life cycle which are key to understanding when assessing a site. These are Annual, Biennial, Perennial and Invasive weeds.

Annual weeds

Annual weeds have a one season life cycle. This means that they complete their growing from seed to seed in one calendar year. Therefore controlling the weed before the seed is formed is critical to controlling the weed. Early flowering should be the latest time of treatment otherwise seeds can spread which will lead to a net increase in weed growth in an area. Examples of annual weeds are chickweed and annual meadow-grass.

Biennial weeds

Biennial weeds live for two years. In the first year, instead of flowers, they produce a rosette – growing leaves and forming storage organs which store the food and energy needed for new growth. In year two, the plant flowers and produces seeds. They need treatment in the first year to help stop the storage organs forming as once they do, they become harder to kill. If in their second year of growth, aim to treat biennials before the Spring growth has started. If well-timed one treatment could be enough however due to variation in growth patterns across species – two treatments are likely to be necessary. Examples of biennial weeds are hemlock and hogweed.

Perennial weeds

Perennial weeds live for three or more years. Like with biennials – the plants storage organs need depleting in order to keep the plant from growing. This means killing the foliage and growing points is important and why perennial weeds need multiple treatments to control the plant. Sterilising seeds and spores is important to help reduce the following year’s germination and stop new growth taking place in an area. The later in the growth stage the plant is treated, the more treatments it will need to be brought under control. Examples of perennial weeds include plantain and creeping thistle.

Invasive weeds

Invasive weeds tend to grow out of control and spread very quickly, effecting the surrounding environment. They can be both native and non-native to the location in which they are growing and are usually perennials. In order to gain control on invasive weeds, it is important to treat the vegetation and any new shoots at close intervals to stop the taking hold or new roots spreading. Repeat treatments are required in order to exhaust the storage organs. But remember, it is important to take note of any legislation around treatment of invasive species like Japanese Knotweed. Examples of invasive weeds are ivy, and bramble.


When it comes to treatment cycles and deciding on a plan for a site – it is important to identify which weeds to prioritise first. Making sure that the plan takes into consideration all types of weeds that are present – and if it doesn’t, making sure there are plans to take care of these separately. Ensuring all key variables have been duly considered will further help ensure the right approach is taken for the treatment site.

Foamstream can be used to control all weed life cycles including controlling invasive species and has the benefit of not being affected by adverse weather conditions allowing it to be used all year round when the weed requires treatment – rather than when the weather allows it.

To read our full e-book on The Complete Guide to Treatment Cycles, you can download it here.

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