Condolences again, a memorial tree is a great idea & the planet could always use more trees. Some have suggested some very nice trees. However a point to consider is, if you plant a fruiting(not just an ornamental) tree there will be fruit to contend with. If they like fruit that'd be great. If they don't care for the fruit then they may want to consider an ornamental tree as there will be no fruit to clean up or draw bees/wasps. Mentioned , cherries, there are ornamental varieties, also purple leaf plum, bradford pear. Crabapples are beautiful but there are the fruit. Flowering dogwoods are great, they come in pink or white(flowers) and have very small berries . Another beautiful purple/pink bloomer is the eastern redbud, but it has little beanpods about 3 or 4 inches long. Witchazel has interesting small yellow flowers that bloom in Jan. or Feb. when nothing else is.
Crape myrtle is actually a large shrub, however, it has loads of beautiful flowers and here in the states it blooms almost all summer long.
Yes a call to a local nursery would give you a better idea of what's available to that clime & may also have other trees not thought of by the helpful, wonderful people of CS.
Whatever you choose, it is a wonderful idea that will loft the memory of their child in its branches up to the sky year after year!
RE: What are you listening to right now?
Today - Jefferson Airplane