My headcanon is that wizards have a poor sense of appropriate scale, because Undetectable Extension Charms. Why not have a greenhouse big enough to house an elephant? How else will the pets (and the kids) exercise when it's snowing?
My dream greenhouse. Gardener's Dream Greenhouse: A superb rendition of the iconic Victorian-era conservatory, the design of this fully functional greenhouse is based upon the renowned Conservatory of Flowers in San Francisco’s Golden Gate Park.