That's a cheap increase in this market. 10% has been the norm I think lately. I have a few friends that have been forced to move because of it. Huge rental scarcity in western washington.
The concerns you have are pretty moot as you're not under al lease any longer unless you rolled month to month. The shrubbery and other yard maintenance usually falls on the burden on the renter. The water can be a hazard, but a lot of fridges are crap that do that.(mine included). I do a crap job at keeping my houses landscaping up to par and little stuff around it, but I undercharge supremely and don't make any one do much outside of the interior.
The landlord isn't doing a good job protecting himself on the rent case by emailing it to you. It really depends on your relationship. I'd of got it in contract and signed in blue pen for an increase.
Also 30 days notice for rent increase up to 10%. 60 days for 10% for 12 year period.