I just learned the kanji 芸 (げい) For “Acting” but 演技 (えんぎ) is acting and 園芸 (えんげい) is gardening. I already get えんぎ and えんげい mixed up. Is this a joke to you, Japan?
I think this is a good case for a kanji that you understand better if you look it up in a dictionary. Wanikani purposefully uses only 1 or 2 readings per kanji to make the learning experience smoother/easier, but sometimes (especially on later levels) a lot of the nuance is lost if you try to describe the word with only a single English word.
Wanikani also sometimes uses synonyms or a somewhat similar meaning word (that usually work well with certain vocabulary words) for the kanji translations which is the case here. If you look up 芸 in jisho.org you’ll see that it is translated as technique or art (etc.).
Now, when you think of 園芸 as “The art of gardening” it suddenly makes more sense. 
Definitely recommend looking up words in a dictionary if you run into similar confusions in the future. 