wanting to order a plant of brunnera macrophylla 'silver heart' after seeing a photo in a gardening catalog. is this one of those plants that will not tolerate our summer heat and humidity? the growing guidelines listed are for zones 3-8, shade to part shade. i can grow hosta but have never tried one of these. anyone having success in the warmer parts of the state? or will it behave like a fuchsia does and melt when it gets hot?