This sounds like a great project! I have archives on #disability, but as of yet don’t have a lot of information on gardening for people with visual impairments.
Your plan sounds great so far. Mostly, my advice has to do with safety.
- Create wide, clear, even pathways
- Consider infrastructure like railings, to provide a tactile pathway
- Avoid elements that attract rodents (like hügelkultur), because if droppings are not seen soon enough to be avoided, there is a risk of hantavirus
- Avoid leaving dry patches of soil (try to cover all soil with plants or mulch), so that cats don’t leave droppings: this reduces the risk of inhaled toxoplasmosis
- Don’t use plants like Digitalis, where touching them too much can cause cardiovascular problems: research the chemical interactions of plants you have in mind.
- Don’t plant anything with thorns.
- Avoid tall grasses where creatures like ticks can live (these are hard to see or feel for a visually impaired person, and carry Lyme disease)
- Remind the client to get a tetanus booster if needed
(Sorry about the disease-heavy advice: I took too many public health courses).
The only other thing I can think of is using sound to create a sense of location or directionality: maybe something like wind chimes or bells, or a flowing water feature?
Also, features like bird baths, bird feeders, and bird houses attract songbirds, which add to the aural ambiance: sound is a dimension of the garden experience a lot of us sighted people don’t fully appreciate (I appreciate it even less because I am hard of hearing on one side).
If any followers want to add suggestions, please do!