Prize-winning crossword

When all the answers are in place, the letters in the odd-numbered squares from 1 to 17 and the even-numbered squares from 14 to 30 will spell out the common names of two plants, perhaps connected to the answer to 22 down.

ACROSS

8 Of a plant, one that 25 downs continually over a season (9) 9 Small stream (4) 10 ‘___ Flower’ or ‘___ Bells’, common name of heuchera (5) 11 Long-tailed crow with a noisy call (6) 12 Small songbird (3) 14 and 25 down Plantsman and current owner of Bressingham Gardens (6,5) 15 Children in ___, BBC charity (4) 16 500 sheets of paper (4) 19 Weaving frame (4) 21 Graceful water bird (4) 23 Lack of interest or concern (6) 25 Pollinating insect (3) 27 Succulent plant (6) 28 Spring month (5) 29 14 across ___, teenager created by Sue Townsend (4) 30 US female singer of the 1986 chart-topper Chain Reaction (5,4)

DOWN

1 Type of wheat (5) 2 Modified leaf, like the ‘flower’ of poinse ia (5) 3 Looked with difficulty of concentration (6) 4 Tall plant of the verbascum genus with woolly leaves and yellow flowers (7) 5 Earth, water, air or fire? (7) 6 Fast-flying, predatory insect (9) 7 Plant suitable for a rockery (6) 13 Anger (3) 14 Useful local facilities (9) 17 Former local government region of eastern Scotland (7) 18 Month of Muslim fasting (7) 20 Lyrical poem (3) 22 Object that might be the first half of either of the hidden words (6) 24 Book describing culinary and medicinal uses of plants (6)