June Gardening Checklist for Philadelphia & Delaware

1. Get the Pruning Done

It’s time to prune spring-flowering shrubs such as mountain laurel, rhododendron, azaleas, lilacs (when done flowering), and shrub roses (to encourage continued blooms). After a good pruning, be sure to scratch in fertilizer and water well. This will encourage new growth and put your plants in a good position to mature and bloom again next season.

2. Try Something New with Your Containers

Containers can add seasonality to your garden. You can go the traditional route, try colorful combinations or varieties you’ve never planted before. Or, grow some interesting plants that may not fit your growing zone year-round-try tropicals such as bananas, succulents and cactus such as mangaves or aloes, and other rare or off-beat plants.

3. Visit Garden Stores and Nurseries for Plants and Ideas

Philadelphia is blessed with gobs of great garden stores that somehow all have interesting plants and inspiring styles. Make a list of the ones you want to visit this summer. Here are a few to get you started: City Planter, Urban Jungle, Terrain, Rhoads Garden, Greensgrow, Vault and Vine .

4. Continue Planting Trees, Shrubs, and Perennials

Get your new plants in the ground now and give them a deep watering in their root zones to get them established (don’t rely on sprinklers and drip systems when establishing plants). A few ideas for planting this season include a focus on native plants: native ferns (sensitive fern and Christmas fern), native perennials (butterfly milkweed, blazing star, blue lobelia, wild bergamot, foxglove beardtongue, mountain mint), as well as native shrubs and trees (paw paw, spicebush, valley oak, dusky willow, narrowleaf willow, Pacific willow, water birch). Many of these plants are available from these online and local nurseries: Proven Winners, Linden Hill Gardens, American Meadows, American Beauties Native Plants, and Bluestone Perennials.

5. Harvest Rhubarb & Asparagus

June is typically the last month to harvest rhubarb and asparagus. When it comes to rhubarb, you don’t have to wait for their stalks to turn all red. A good rule of thumb is to harvest when stalks are 10 to 15 inches long. When they’re ready, pull the stalks out of the ground with your hand or cut them close to the base. For asparagus, harvest the last of your asparagus in early June—typically the harvest begins in late April and lasts four or five weeks, but weather may push harvest up or back a week or two.

6. Add to the Vegetable Garden

There are a number of ways to expand your edible garden that don’t require you to build more raised beds. Here are just a few ideas: plant dwarf citrus trees; install a simple arbor or wire along a fence for squash, cucumbers, beans, or Mexican gherkin; grow herbs and tomatoes in ceramic pots (they love the extra heat); or turn a bare wall into a mini edible garden using a felt system such as Florafelt Pocket Panels.

7. Do a Little Garden Maintenance

One of the most critical gardening tasks for this time of year is giving the drip and sprinkler system a once over. Run each irrigation station to check in on everything: Inspect sprinkler heads for functionality and adjust them to avoid overspray and make sure drip emitters aren’t clogged. After your irrigation system is set for summer, it’s time to give the garden a good mulch to help retain moisture and prevent weeds (don’t do this before you check your watering system—you'll just make the work more difficult). You can also spend time removing spent flowers from plants for a fresh start to summer.

8. Plant Flowers for Late-Summer and Autumn Blooms

To enjoy blooms all summer long and even into fall, plant some floriferous plants right now. Some of the best varieties for lots of blooms are asters, black-eyed Susan, coneflower, dahlias, mums, multi-branching sunflowers, and cosmos. You can find many of these at Proven Winners. A good selection of different colors and cultivars is also available at Select Seed.

9. Buy Heirloom Seeds and Plant Now

Philadelphian William Woys Weaver is a pioneer in the preservation of edible seeds, crops, and their stories. For almost 40 years, he has preserved heirloom seeds from America and around the world. You can buy seeds from his Roughwood Seed Collection through Baker Creek Heirloom Seeds. Why not give something new a try this year? The seeds are selected based on providing great-tasting food so no matter what you pick, you can’t go wrong. We suggest try the Buena Mulata Hot Pepper and the Tamboura Melon.

10. Visit a Botanic Garden

Take advantage of being close to some of best public gardens in the world that are all within an hour drive of downtown Philadelphia. A tip: If you go early in the month, they may be a little less crowded since vacation season won’t have kicked into full gear yet. For some local touring guidance, be sure to also check out America's Garden Capital, a website that fills you in on 30 public gardens, arboreta, and historic landscapes, all located within 30 miles of Philadelphia. And keep in mind that many of the nearby gardens such as Longwood Gardens, Chanticleer, Mt. Cuba Center, and others offer regular classes and educational events.