Katsu-san, adding plants around the watefall would be beautiful and add a natural touch to something clearly recognizable as man-made.Good choice and I am very much looking forward to anything garden-related as I love nature as a whole.
Did you know you that, eventhough perhaps on novice level, you can take english classes too at Duolingo? And with your language/cultural background as a starting point (by setting the website language to japanese you will understand everything even better and perhaps feel more comfortabe in a new surrounding).Another suitable resource would be EnglishClass101 where you can listen and watch a lot of practise material in your own time and comfort.For your consideration

naturally I will be around to help through Private Messaging.
Looking forward to seeing your garden/modeling/english develop,Katsu-san !