Instructables user writes:

From mid-June to mid-July you can’t turn the corner in the area where I live without seeing an elder tree in flower.

At this time of year the fist sized bunches of tiny white flowers make a great cordial which is really tasty with sparkling water, ice and a slice of lemon. Be sure to leave some flowers on the tree though as come Autumn the berries make a great wine!

The resulting cordial has a sweet, floral, refreshing taste which is one of my favourite summer drinks.

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How-To: Elder Scottish Rose Cocktail