What June Asks of a Garden

June is when the garden stops asking for patience and starts asking for attention.

The spring show is behind us. The lilacs and viburnums have finished, the peonies have dropped their last petals and everything green is growing with real ambition. Around the Brandywine Valley this is the month a garden decides what kind of summer it’s going to have, and a little work now pays for itself through September.

• Prune the spring bloomers, and do it soon. Lilac, viburnum, weigela and any shrub that flowered before Memorial Day sets next year’s buds on this year’s wood. Prune them within a few weeks of bloom and you shape the plant. Wait until August and you’re cutting off next spring’s flowers. It’s one of the most common mistakes we see, and one of the easiest to avoid.

• Deadhead like you mean it. Spent blooms on Salvia, Nepeta and hardy geraniums aren’t just untidy. They’re a signal to the plant that its season’s work is done. Cut them back and most perennials will answer with a second flush. Nepeta in particular is generous about it. Shear it nearly to the ground after its first bloom and it comes back fuller than before.

• Watch the hydrangeas. Hydrangea quercifolia, the oakleaf, is just opening now and it’s one of the finest shrubs a garden in this region can hold. Established plants need little from you in June beyond water in a dry stretch. Newer plantings want a deep soak once a week, at the base, in the morning.

• Give containers their rhythm. By mid-June, container plantings are hungry. A water-soluble feed every week or two keeps annuals blooming instead of stalling. If a container looks tired already, it’s usually the feeding, not the plant.

June rewards the gardener who shows up. If your landscape is asking for more attention than your calendar allows, the EHS professional gardening team spends this month doing exactly this work on properties across the region, and we’re glad to talk about yours.

Ann Waters is Head Horticulturist at Eastern Horticultural Services. She is a University of Delaware graduate and completed the two-year Professional Gardener Training Program at Longwood Gardens.