border box bush divide formal garden grass green hedge leaves park path plant square stones trimmed abundance abundant allium flower grow head many mauve natural nature onion pink profusion stems cranebill flowers gardens geranium pale pink pink petals pink textures plants rose rose pink shrubs summer. England english Great Britain lilac shrub spikes spring syringa cultivar Eryngium gray grey prickle Prickly sea holly silver spine spiny alkekengi bladder cherry chinese fruit hozuki hōzuki japanese lantern leaf orange Physalis winter