There are few plants that demonstrated a true shade of blue foliage for the garden, Normally the attractive of plant is flower since Hostas are noted for their brightly colored variegated leaves, the best one that all gardener known hosta leave come in many variegated patterns. Actually Hosta leaves aren’t blue, but the leaves are green with a waxy coating which  produced when new leaves are emerging.when season progress the wax decline from sun exposure ,water , temperature etc, after that he green leave underlying will appear. That mean why many hosta emerges with blue-green leaves, but becomes green in later. How long of blue color or waxy retain in the leave up to many factor,some may retain longer some not based on growing conditions.

Some of Favorite Blue Hostas

Blue Heaven	18 " T x 24 " W Heart-shaped Silvery blue leaves. The clumps are topped with 18" spikes of lavender flowers
Elvis Lives	18" T x 38 " W Narrow blue-green leaves , Pale purple flowers
Krossa Regal	40" T x 70 " W Wavy blue green leave and a graceful. lavender flower appear on exceptionally tall 4-6 foot’
Blue Mammoth	18" T x 24 " W Heart-shaped leaf on blue green color, Bell shape with lavender flowers
Big Daddy	25" T x 47 " W Grey-blue leaves with prominent veins, Grayish-white bell-shaped flowers.
Blue angle	32" T x 70 " W A very large tiered mound of heavily textured blue leaves that can be as wide as 18 in. in diameter. Purple/Lavender Flower
Deep Blue Sea	15" T x 36 " W Thick metallic blue leaves with cupped and heavily corrugated. Light lavender flowers
Blue Umbrellas	31" T x 59 " W Large specimen with big blue-green leaves a downward cup shaped. Pale lavender large flowers.
Blue Cadet	16" T x 36 " W Medium size hosta with blue-green heart shaped leaves. Medium Lavender flower
Restless Sea	17" T x 32 " W A medium size hosta with large intensively curled leaves edges leaves is intense blue, blue-gray green, green in summer Lavender flowers
Blue Jay	18" T x 15 " W Hybrids a seedling from Hosta 'Dorset Blue The intense powder-blue round cupped heart shape on leaves Becomes green later in the season. The clump is topped with light lavender flowers
Abiqua Drinking Gourd	22" T x 46 " W Heavily textured, huge blue-green leaves cup and twist White flowers.
Baby Bunting	6" T x 12 " W Blue hosta in smallest size (mini hosta) Rounded leaves about 2 inch wide in maturity that begin grey-blue in color, later becoming dark green. Purple flowers.
Camelot	18" T x 48 " W Medium hosta with a thick & heart-shaped leaves are bright blue in spring. A leaves are moderately corrugated and slightly cupped. lavender flowers
Dorset Blue	6" T x 15 " W (Mini blue) Rounded intense blue leaves, looks like 'Blue Moon', but grows better. Heart-shaped blade. Heavily corrugated, thick substance. Pale lavender flowers open in mid- to late August.