Historical clue formulations

• Prickly shrubs — 2021-11-19
• Certain rough patches — 2020-02-27
• Brambles — 2019-09-23
• Stickers forming a patch — 2018-11-04
• Rabbit homes, maybe — 2015-02-27
• Sticking points? — 2012-06-09
• Prickly plants — 2010-03-24