June Calendar

Memorial Day weekend is the end of the gardener’s leisure.  In the weeks preceding the holiday, everything in the garden that needed tending should have been tidied up.  Plants started indoors, in a cold frame, or in a greenhouse are ready to be moved to their permanent home.  Seeds sown out of doors may be sprouting.  If you’ve done this, keep a close watch and thin the rows when they produce the second set of leaves.

In flower borders or vegetable gardens a rigorous weeding followed by a proper mulching should eliminate most additional weeding in the coming summer months.  Timing is of the essence.  If you’ve missed eliminating the thistles it’s too late.  If you haven’t gotten the grasses out of the bed, they will soon seed and it’s all over.

Container planting and hanging baskets are ready for their debut.  Set out the lawn furniture and relax while you can. 

Wave Hill Garden Chairs

WEEK ONE

If you’ve planted seeds out of doors, sprinkle every day until they germinate.

Continue vegetable planting.

Plant nasturtiums and sunflowers.

Set out tomato seedlings or transplants.

Apply general fertilizer to perennials.  Heavy rains may have leached out nutrients.

Plant waterlilies and tuberous begonias outdoors.

Thin tiny fruits in peach, plum and apple trees. Six to eight inches is good.  Doing so will avoid too heavy a crop one year and nothing the next.

A Manhattan Brownstone Window Box Remember to fertilize and water window boxes regularly.

Trim evergreen hedges after the first flush of new growth.

Every few weeks adjust the ties on plants’ supporting stakes.

WEEK TWO

Be careful working the soil if it has been unusually wet.

When setting out annuals or perennial divisions, give them a dose of liquid fertilizer, but not onto dry soil. Water first.

Finish sowing annual seeds as soon as possible.

Thin seedlings that are already sprouting.

Plant all summer-flowering bulbs.

Roses and Clematis Streetside at a Manhattan Apartment Building Make sure supports are in place for climbing vines and start training new growth.

Fertilize clematis with a handful of bonemeal.

Last call to prune pine trees.  The safest time is in the first two weeks of June.  Don’t snip off the top.  Trim back branches only where necessary.

When new shoots of phlox and bee balm are about eight to ten inches tall, remove all but four or five stems to improve air circulation.

Container-grown Calibrachoa Begin a regular fertilizer program for container plants and hanging baskets.  Feed every two weeks.

WEEK THREE

Fertilize roses after the first bloom is over.

Deadhead flowers and remove unripened seed pods.  This is important for appearances, reduced weed production and a possible second bloom.

Alchemilla in Second Bloom, Mid-summer Shear back low-growing plants to produce a second bloom.  Responsive to this treatment are Alchemilla mollis, Geranium sanguinium and Artemisia.

Early summer is a good time to prune or lift shade trees.  You can see precisely what you will lose.

Add mulch if needed, but not on dry soil. Water first..

It’s too late to move perennials.  If they need a little room and air, cut off a few of the side shoots.

Hydrangea 'Annabel' Adjust hydrangea colors towards pink or blue by increasing or decreasing soil acidity.

WEEK FOUR

Continue to pinch or cut off faded flowers from annuals and perennials.

It’s time to cage or stake tomatoes.  If you stake them they will need to be tied periodically and trimmed.  Remove suckers or short leafy stems that sprout in the axils of the side or main stems.

Flowers will remain fresh longer if cut with a sharp tool, and if foliage is stripped from the parts that will be under water.  Let flowers stand overnight in a bucket of water before arranging.

Most flowers will need staking, but if this is not your game consider daylilies.  Blooming in July and August, they are fine on their own.

Spirea Vanhouttei, the Aptly-named Bridal Wreath Prune shrubs and vines that have bloomed as soon after blooming as possible.