You are probably right that these activities have become more difficult for her. It also is more difficult for a person with dementia to initiate an activity, even things they enjoy. Try to identify some areas of the activity that can be modified for her. Gardening is an activity that can be adapted. Raised garden beds or containers might help. Indoor plants and herbs require less physical strength. Try doing an activity with her, which will help her to initiate, and give you a chance to gauge her responses. Ask for her help or advice with your own garden. She still has a lot of knowledge you can tap, and you still have time to enjoy her company.