Phenology – time of budburst in spring and budset in the autumn is critical for ash. The terminal bud, which is flanked by two laterals is the first to break in the spring. If this is damaged by frost, the two laterals take over, and a fork develops which is an undesirable timber characteristic. We score the time of budburst in all our orchards and provenance trials, using a five-point scoring system. The data collected is used to determine which provenances are likely to perform best at different locations. We are currently looking at provenances from France that might be better suited to growing in our projected warmer climate, but will still flush later than those provenances from further south. Provenances from more southerly latitudes or more continental regions flush earlier than our native ash, but then suffer from frost damage. Even taking in to account the projected warming of our climate, late spring frosts are still likely to occur.