Game of Thrones may have Highgarden and its castles, but modern architecture incorporates some really high gardens in city centers, and some really wide gardens over airports and factories.  

Willow saplings can be bent and twisted into some incredible shapes.  Take a look at the work of some of the best environmental architecture from around the world.  

Figure out why it's called lost wax casting and what the process entails.  

One of the 9 hemlock species, the one that grows up the Appalachians from Georgia to Canada, will probably be gone by the end of this century.  It will still exist in arboretums and on some private properties, and maybe in the far north, but its great swaths of forest will most likely have rotted out because of a non-native pest.  Another reason why you should never transport firewood! - you risk spreading pests living in the wood to new areas.  

Flower diplomacy? Yes, we got 3000 cherry trees from Japan in 1912 thanks to the work of Elizabeth Scidmore, a diplomate's wife. In 2012, we made a gift of 3000 dogwood saplings to Japan to commemorate the event. Some of those flowers went to memorials honoring those who lost their lives in the Fukushima nuclear disaster.  

Hemlock sounds dangerous because we have a vague of it being used as a poison to kill Socrates.  This post explains how the common name of that plant came to be associated with a family of large conifer trees in North America.