How we grew online market share by beating the industry average CTR (by 657%!)

TP Knotweed


TP Knotweed specialises in the safe and rapid treatment & removal of the nightmarish Japanese Knotweed. Over 850,000 UK homes are affected by this invasive plant species — a non-native weed that can damage and destroy the foundations of properties. 

The sheer presence of this plant can cause building works or house sales to grind to a halt (you can’t sell without first having it removed or at least having a treatment plan in place).

Zest has worked with TP Knotweed for the past seven years, establishing the company as one of the largest and most reputable Knotweed removal specialists in the UK via our Growth Engine solution.

This “done for your” approach to growth marketing means we drive traffic generation and lead conversion on our client’s behalf to help meet and exceed revenue goals. 

However, the Knotweed removal industry is notoriously competitive; only so many people search for these specific services every year. Generating more traffic when there’s a glass ceiling to search volume is impossible. 

Therefore, our objective was to take more of the existing market share


TP Knotweed’s Ads account has been set up following a strict AIDA format (Attention, Interest, Desire, and Action). We used search ads to target Knotweed-related keywords, display ads to grab attention and generate interest, and remarketing to reinforce desire and encourage action.

This three-pronged approach delivered strong results across the board. The conversion rate sat far above the industry average, while we managed to lower cost-per-click (CPC) via ongoing optimisation. This, in turn, meant we achieved a lower cost-per-acquisition (CPA), and ultimately, a highly profitable account, boasting a 1,315% return on investment (ROI). 

Still, we wanted to do more. Knotweed removal is highly seasonal because it grows when it’s warm, making it more noticeable, and the need for removal is often front of mind as the housing market sees lifts between spring and autumn.

So, to capture more of this seasonal audience, we turned our attention to click through rate (CTR) to grow traffic to the site. 

Despite having a strong CTR already – 62% above the industry average – we knew if we could increase it while maintaining (or lowering) CPC and maintaining (or increasing) conversion rate, we’d see more quality traffic and retain the account’s levels of profitability.

Here’s how we did it.


To start funnelling more high quality, incentivised traffic towards TP Knotweed, we employed several CTR-boosting tactics. 

Beyond standard Ad account optimisations, such as expanding negative keywords and building out smaller ad groups with fewer keywords to improve relevancy, two approaches, in particular, took root and delivered the results we craved: image ad extensions and extensive split testing. 

  • Eye-catching image ad extensions: We were fortunate to access Google’s new image ad extensions when they were still in the beta stage. This extension allowed us to display a relevant image next to the text ad on the search engine results page (SERP).

    By creatively selecting the right images at specific points throughout the year, we could help searchers understand what Knotweed looks like at that moment in time. This enabled the searcher to identify Knotweed, first and foremost, while also strengthening TP Knotweed’s expert credentials.
TPK Knotweed Ad Example
  • Split testing galore: After working together for seven years, it would’ve been easy to rest on our laurels and let things run on autopilot. But that’s not our style. We’re constantly looking to exploit even the finest margins to get results for our clients, which leads us to obsessively test EVERYTHING. Here’s a flavour of what we tested:
    • Ad copy: Ad copy has to tick all the boxes for Google while also resonating with the end-user. To find that perfect balance, we carefully analysed reviews and forum posts related to Knotweed. And by understanding the associated pain points, we could mirror the language used in our ad copy to make it more relatable. Finally, we created a bank of hundreds of headlines and descriptions to test.


    • Ad extensions: In our battle for attention, we experimented with more ad real estate, more links to click, and different landing pages.
    • Devices: There are several steps in the journey towards hiring a Knotweed removal specialist. By split testing devices (and the types of ads we ran across each), we found that our awareness and interest campaigns worked best on mobile, with users doing their initial research on smartphones or tablets. Meanwhile, at the desire and action stage, users favoured their laptop or desktop to complete the enquiry form.


We saw some incredible numbers following our account optimisations and ad experiments for TP Knotweed. The standouts include:

  • A 367% increase in CTR year-on-year (from 3.89% to a mammoth 18.7%);
  • A 131.6% increase in conversions year-on-year;
  • And a 1,315% return on investment (ROI).

However, perhaps most impressive of all was the fact that we managed to beat the industry average CTR by a whopping 657% — smashing our goal of grabbing a larger share of the search volume.   

TP Knotweed CTR Increase

return on investment


increase in click-through rate


increase in conversions

“Since day one, Zest has consistently pushed our marketing to the next level. Relevant, timely, and creative, this latest campaign is the perfect example of their out-of-the-box thinking and attention to detail. We’re delighted with the results — and we can’t wait to see what they do next!”

Tom Payne, Managing Director, TP Knotweed


return on investment


increase in click-through rate


increase in conversions

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