Best grown in rich, medium moisture, well-drained soils in part shade. Tolerates full sun only if grown in consistently moist soils. Soil pH affects the flower color (blue in highly acidic soils and lilac to pink in slightly acidic to alkaline soils). Add aluminum sulfate to the soil to make the flowers bluer or add lime to the soil to make the flowers pinker. Begin soil treatments well in advance of flowering, as in late autumn or early spring. Plants generally need little pruning. If needed, prune immediately after flowering to avoid harming the bloom for the following year (plants bloom on old wood). Prune out weak or winter-damaged stems in early spring. In USDA Zones 5 and 6, mulch plants with a thick layer of bark or peat moss in late fall. Plants are only reliably winter hardy to USDA Zone 6. Plants can be grown in USDA Zone 5, however, if sited in protected locations with good mulch and possibly a burlap wrap, but they may lose significant numbers of flower buds or die to the ground in harsh winters, thus respectively impairing or totally destroying the bloom for the coming year.
Big leaf hydrangea (H. macrophylla) is a deciduous shrub with a rounded habit that, in the St. Louis area, typically grows 3-6’ tall and as wide unless damaged by harsh winters or pruned smaller. It generally features dark green, serrate, obovate to elliptic leaves (4-8” long) and large clusters of long-blooming summer flowers in lacecap (flattened flower clusters of small fertile florets with scattered showy sterile florets often forming a marginal ring) or mophead (globose flower clusters of mostly showy sterile florets) form. 'Blaumeise' (translates from German as titmouse, blue tit or blue sky) is a compact lacecap cultivar that is sometimes marketed under the trade name of BLUE TITMOUSE. It is a member of the Teller Series of hydrangeas (Swiss series featuring names of native European birds), and is also sometimes commonly sold as 'Teller Blue', 'Blue Tit' or 'Blue Sky'. It grows to 3-5’ tall and as wide, and typically blooms on old wood (flower buds are produced the previous fall and overwintered). It may be grown in acidic soils for its blue florets or in alkaline soils for pinker florets. In acidic soils, the large showy sterile florets in the outer ring of each flower head are sky blue. In alkaline soils, the sterile florets emerge pink but often age to a pink-blue mixture. By reputation, this is one of the best of the blue lacecap hydrangeas.
No serious insect or disease problems. Some susceptibility to bud blight, bacterial wilt, leaf spot and mildew. Aphids are occasional visitors.
Group or mass in a sheltered location in the shrub border. Also a good specimen or accent for foundations and other locations near homes or patios. Hedge.