Bonzi: a trusted plant growth regulator

The integration of plant growth regulators (PGRs) into the production regime can help you achieve the pace and precision of control needed.

About

Just as with pest and disease control, the use of cultural methods is imperative to help regulate plant growth rate. However, like in pest control, manipulating irrigation, nutrition, temperature and light is rarely enough to achieve sufficient control of the pace of plant growth - especially in the variable conditions of spring and early summer.

Only by careful integration of plant growth regulators (PGRs) into the production regime can you achieve the pace and precision of development needed. These products allow growers to either accelerate development or slow it down in response to changes in demand or unseasonal weather.

Bonzi, which Fargro markets in partnership with its manufacturer, Syngenta Ornamentals, remains one of the most widely-used and best known PGRs – and with good reason. It is one of the few PGRs to hold an on-label approval for use on protected ornamentals, meaning operators can trust its effectiveness and safety – making it a long-time favourite of protected bedding and pot plant growers. Bonzi, which contains the active ingredient paclobutrazol, regulates key hormonal pathways within plants. This allows it to produce more sturdy, vigorous, and compact plants with enhanced flowering, shelf life and colour and, at timings necessary to meet marketing schedules.

Bonzi can, therefore, help growers manage impacts of adverse weather or market conditions to produce high quality plants on a timetable that supports commercial sales.

Product details

Paclobutrazol, the active substance in Bonzi, inhibits gibberellin production at several points.

Bonzi contains the active substance paclobutrazol, which inhibits the production of the plant hormone gibberellin. Giberellin a key regulator of plant growth, which also influences the production of other hormones that control important plant physiological processes. Bonzi can have a useful long-lasting effect – meaning that small, frequent application may be the best way to fine-tune growth according to conditions. However, it is important to avoid run-off as it can be taken up by the roots or persist in growing media and capillary matting – with implications for predictability of results and impacts on following crops.

The label allows foliar spray application at a range of rates and timings based on more than 30 years of continual trials, enabling us to help you tailor applications to achieve the specific effect you may be looking for.

Key aspects of application

Effective application is dependent on three factors; the crop that is being treated, its growth stage and the environmental conditions. When using Bonzi on a new variety we advise testing on a small batch of the crop to ensure the application results in the desired changes. As environmental conditions directly effect results, trials data from non-comparable environmental zones should not be used as a guide for UK applications.

In order to get the most out of the application of Bonzi it is important to keep two things in mind. The active ingredient, Paclobutrazol, takes between 30 minutes to one hour to be absorbed by the plant.

As such it is essential to maintain leaf wetness for this time period. Application, therefore, should take place during a period of high humidity to ensure the leaves will remain wet, such as the evening or morning. However, if these conditions can’t be met then the crop may need to be rewet to prevent drying during uptake.

Paclobutrazol is very mobile within the xylem but not in the phloem. This means that movement within the plant leaf is good, but paclobutrazol will not travel from the leaf back to the stem - so it is important to ensure good coverage.

Bonzi sees stems and leaves divide and expand more slowly, slowing stem growth and internode length, as well as leaf expansion, but this is achieved without affecting branching, leaf number or root growth. These smaller leaves are also of a stronger green colour due to higher concentration of chlorophyll pigment. This means that Bonzi is excellent at combatting the stretching tendency of many annual and perennial species grown for the peak spring and summer seasons.

Bonzi also increases the concentration of plant stress response hormones, making the plants more tolerant of environmental stresses – such as drought.

Syngenta Ornamentals

“Syngenta has more than 100 research sites around the world including the famous Jealotts Hill in Berkshire which has some of the most advanced laboratory and greenhouse research facilities in the world,” says Syngenta Ornamentals UK business manager Daniel Lightfoot.

“We spend around 8% of our turnover on R&D, including on thousands of trials generating really robust data over many seasons to give us a sound understanding of the way our products work. That in turn means we can support partners like Fargro to help you use products such as Bonzi with confidence on your own crops and under your own nursery’s specific conditions.”

“Applications to maturing plants can control both flower size and flower stem length as well,” adds Daniel. “There are also helpful improvements in leaf colour.” “It’s not only highly effective, it has also proved over the years to be very crop-safe and that makes it easy to use.”

Read customer tesimonials

Double H is a family business established in 1961 that focuses on providing innovative, beautiful products to their customers. The business primarily grow roses, chrysanthemums and orchids supplying some 4.5 million plants to a number of UK supermarkets. Supplying supermarkets comes with stringent specifications for plants.

Mariusz Szejna, Growing Manager N&R Block, says, “We use Bonzi to meet specification of the customer, untreated roses would be too tall and as such not meet the specifications, with roses this is particularly important as a tall rose in a short pot does not appeal to the consumer”.

Industry experience and experience internally at Double H give the team confidence in using the product. Double H have been growing roses for 7 years and have used Bonzi throughout that period. Mariusz goes on to say, “Bonzi has one of the stronger PGR effects, for us that is important as it means we do not need to spray as often”.

This is a benefit of Bonzi that growers who are finding labour issues, both shortages in general but also of qualified spray operators, meaning that they have to priorities task particularly useful.

Blofield Nurseries is a family owned and run company, based on the outskirts of Blofield village, near Norwich. Growing under glass, propagating and utilising various stock areas Blofield Nurseries specialise in azalea, camellia, pieris and rhododendrons. Producing over a million rooted cuttings, 350,000 P9 liners and 100,000 two litre shrubs supplied to wholesalers.

Blofield's Nurseries crops have to meet set specifications they use Bonzi to ensure these are achieved, “We find that the results are consistently what we need to grow quality plants to the spec requested by our customers.” John Ellerbrook, Owner and Nursery Manager at Blofield nurseries.

John goes on to highlight the importance of personal experience with Bonzi that has created the trust and confidence the company now has in the product. “We have relied on Bonzi in our growing method for many decades. I have used Bonzi for just over 20 years and my father for many years before me.”

Use plant protection products safely. Always read the label and product information before use. Further detail on warning symbols and phrases is included on the labels and leaflets.