hey folks! i planted 5 bob gordon and wylewood cultivars of elderberry in my property 3 yrs. ago. they have grown vigorously to 10ft. and have a doz. big cymes per plant. this year is the 1st year they have flowers and fruit but they aren't changing to purple yet even after a light frost 3 days ago. everything I've read about american elderberry and these cultivars say they grow to zone 3. I'm on 3b/ 4a line and on some elevation so we get less frosts than the lowlands . we also have had a warm summer. they should be ripened by now. maybe because its their 1st year fruiting they're a little behind? anyone in my zone that is growing these that could reflect on this? any info appreciated!