Black locust 'Purple Robe'

Keep in mind when planting that Purple Robe is thought of as hardy, so it can be safe to leave outdoors for the majority of winter (although if in doubt, using a row cover is often a good idea). A soil ph of between 6.1 and 7.8 is ideal for Purple Robe as it does best in weakly acidic soil - weakly alkaline soil.

As Purple Robe is hardy, ensure temperatures are mild enough to plant out - wait until after your last frost date to be on the safe side.