Prize-winning crossword

When all the answers are in place, the letters in squares 1 to 6, then the odd-numbered squares from 7 to 31, will spell out the completion of this quotation from gardening writer Sydney Eddison: ‘Gardens are a…’.

ACROSS

8 Famous Oxford museum, based on the collections of the Tradescants (9) 9 Strong desire or impulse (4) 10 Surname of TV’s Del and Rodney (7) 12 Of fruits and seeds, with the outer covering or pod removed (6) 13 Lyric poem (3) 14 Flowing out, as the tide (6) 17 Middle Eastern country, capital Baghdad (4) 18 Male monarch (4) 19 Lubricates (4) 20 ___ anise, fruit used in Asian cookery (4) 21 Old coin worth 21 shillings (6) 22 Spike of corn, perhaps (3) 24 Confer holy orders on (6) 26 Charge a President, perhaps, with misconduct (7) 30 Banana genus (4) 31 Beatles song, and an award-winning variety of rose (9)

DOWN

1 Quick (4) 2 US state with capital Columbus (4) 3 Underground part of a plant (4) 4 Underground railway in Paris (5) 5 Of a bird, in flight (2,3,4) 6 Meaning of the botanical term plenus (4) 7 Willing, or pleasant (9) 11 One who makes fitted clothes by hand (6) 15 Wild flower of the Ranunculus genus (9) 16 1995 James Bond film (9) 17 Set fire to (6) 23 Wash away soap with clean water (5) 25 Not at home (4) 27 ‘Maris ___’, lordly potato variety? (4) 28 Very important person’s assistant (4) 29 ___ carnosa, the wax flower (4)