Urban meadows have the potential to deliver both biodiversity, through species richness and abundance, and wellbeing benefits. Public support for the provision and design of urban meadows can be enhanced by incorporating the preferences of respondents who would use and pay for them. This study investigates preferences for attributes of urban meadows as a biodiversity intervention in urban greenspaces. Using a choice experiment conducted in situ with 563 respondents across three types of sites across three cities in the UK, we elicit willingness-to-pay (WTP) for changes in the range of flower colours, proportion of native species, the number of plant species, and the quality of area for pollinating insects. We experimentally investigated whether WTP was different when respondents were interviewed at either annual, perennial, or control sites, to investigate the effect of hypothetical bias and salience of attributes on preferences. To mitigate the effect of confounding variables, we reweighed observations from each meadow type using entropy balancing. Using a weighted mixed logit model, we found that preferences for a higher range of flower colours were sensitive to meadow type with respondents at control sites having lower WTP. Results for other attributes, however, suggest that our CE recovered similar preferences for urban meadows across each site of interview. Respondents were willing to pay for more colourful, pollinator-friendly meadows with more native species. The relative magnitude of these preferences expressed in WTP terms has implications for the planning and design of biodiversity in urban greenspaces, and these findings suggest that such interventions could present a win-win scenario for people and biodiversity conservation.