What to do in your Northwest garden in June

Plant

Shop nurseries for bulbs planted in 4- or 6-inch pots. For sunny spots, choose agapanthus, calla, canna, crocosmia, dahlia, gladiolus, and tigridia. For shade, you can’t beat tuberous begonia.

Plant balled-and-burlapped or container-grown groundcovers, vines, trees, and shrubs, including roses from the Flower Carpet series.

Grow hotter peppers. Scoville heat units, which measure the fire of peppers, range from practically zero for bell peppers up to 350,000 SHU for habaneros ― but any variety of pepper will develop more heat when grown in a warmer place versus a cooler spot. If you grow your peppers against a south wall, the higher ambient temperature, reflected heat, and protection against prevailing winds will combine to turn up the spiciness of the pepper.

Sow annuals to fill bare spots. In a sunny bed of well-prepared soil, sow cosmos, marigold, nasturtium, portulaca, sweet alyssum, and zinnia. When they become seedlings, transplant them to spaces that have opened up after edibles were harvested or flowers faded on earlier bloomers.

Use groundcovers for dry banks. Exposed, dry banks may seem like daunting places to plant, but many groundcovers grow well on them. Try Arctostaphylos uva-ursi, any kind of thyme, or trailing types of ceanothus, cotoneaster, juniper, or rosemary.

Plant Thai basil and cilantro now, and you’ll have fresh herbs all summer and beyond. Both annuals love sun and ample water, and do well in pots. Start basil from seedlings; to prolong leaf production, pinch off flower spikes as they develop, or let them go to enjoy the purple blooms. Because cilantro germinates quickly, sow seeds directly in the container. Begin harvesting when plants reach 6 inches tall; if you live in the low desert, wait to sow until fall.

Maintain

Deadhead flowering plants. Snip faded flowers to prevent seed from setting, which slows or stops the bloom cycle.

After bloom, dig up spring-flowering irises, Oriental poppies, and primulas, and divide them. Some plants, like Oriental poppies, can be separated root by root; others, like irises, have to be cut apart with a shovel or knife. As you work, throw away or compost woody or dead parts of the root.

Prune candles on pines. Light green, finger-like shoots of new growth on pines are called candles. As needles begin to open, you can break off the top half of each candle to limit growth. This old bonsai trick works well with landscape pines.

Protect

Prevent wormy apples. If last year’s ripe apples had one hole bored into the fruit and one hole out, you had coddling moths (apple worms). If your fruit was riddled with tunnels, you had apple maggots. Both pests will be back, unless you take preventive measures; spray trees with an organic pesticide containing spinosad.

Treat aphids. The insects deform tender new leaves and, more important, spread plant diseases. When you begin to notice a lot of aphids, blast them off plants with a jet of water from the hose. You may have to go through the process two or three times for complete control. In serious cases, follow up with a spray of insecticidal soap.