6 Summer Flowers Martha Grows Year After Year, According to Her Head Gardener

The summer garden is brimming with design potential. As the warmest season of the year, summer gives you the opportunity to explore all of the plants that weren’t available to you during the cooler spring months. Tender, tropical, and cold-sensitive plants are able to grow and thrive in the summer garden, so you don’t have the limitations that frost and cold spells pose. What’s more, summer tends to bring on plants that are taller and more substantial in size and growth ability, adding a new level of visual interest to the garden. 

When designing Martha’s summer flower garden, we try to use as much color as possible. Spring’s pastels are still prevalent in the summer garden, but we also focus heavily on incorporating oranges, yellows, and brighter and deeper pinks and purples. Red will sometimes make an appearance and is found in the various color blends of roses we grow, but Martha favors purples and oranges over reds and yellows, so I keep that in mind as I plant. 

To inspire your summer garden, here are some of Martha’s favorite summer flowers we grow on the farm, including roses, lilies, snapdragons, cosmos, zinnias, and phlox. (We grow all of these in zone 7, formerly zone 5.)

Roses

Roses are the world's favorite flower for a reason. These shrubs add structure to the garden and their bloom power is impressive—many will keep pumping out blooms all the way until winter. Roses come in essentially every color, style, blossom shape, and size that is possible, so they are able to be incorporated into any garden situation as long as you choose the right type. 

At the farm, roses are incorporated into the flower garden where they line the perimeter of the whole garden. We also have two long rows of roses flanking two parallel rows of lilacs, which start to bloom right as the lilacs fade. Additionally, we have a rose cutting garden, which has a couple hundred roses planted specifically for cutting. 

Roses need full sun, rich amended soil, regular-heavy feeding, and regular watering. They have a very specific pruning regimen—Martha likes to follow the old saying “prune after bloom,” which is especially true for the older once-blooming varieties. In addition to pruning, roses also need to be regularly deadheaded (cutting off old faded flowers), which you can do by cutting right above a five-leaflet bud. 

Lilies

Lilies are another sun lover that offer a lot of variety in the summer garden. There are many types of lilies, with differences in size, flower orientation, height, and growth habit. They come in pretty much every color, and many are heavily fragrant. 

Lilies can be grown in rows to be used as cut flowers, which Martha does at her house in Maine. At Bedford, we have lilies planted throughout the flower garden, grown in groups of the same variety or color. We also have a huge pergola that is filled with thousands of orange tiger lilies that bloom every year in late July and throughout August. 

As a perennial, lilies will come back year after year, with some types increasing in size and spreading. They prefer well-draining, loose soil rich with organic matter. Fertilize lilies with granular fertilizer at planting time and again after the flowers fade. They can grow to be pretty tall, so staking may be required. 

Snapdragons

Snapdragons are another favorite of Martha’s. Taller varieties can be grown in rows for cutting or mixed into the flower garden, which is what we prefer to do at the farm. They do better in the front of the garden as many varieties are only 1 to 2 feet tall. 

While snapdragons are technically a short-lived perennial, they are often grown as annuals. We generally start them from seed indoors in the winter and then transplant the seedlings out into the garden later in spring. They like full sun, but will also grow in partial shade. These low-maintenance plants don’t require fertilizer or pruning, though you can pinch plants out as they grow to help with their shape and keep them from getting too spindly. 

Cosmos

Cosmos are a member of the daisy family and key in the summer garden thanks to their height and airy, delicate foliage. There are two main groups of cosmos: traditional cosmos, which come in shades of purple, pink, white, and reddish, and sulphur cosmos, which come in shades of orange and yellow. We like to plant them from seed, as they prefer to be direct sown in the garden once it is warm. They need to be replanted every year, but they very often self-seed where they are happy. 

Cosmos are easy to care for, another reason they’re a great addition to the summer garden. They need full sun, but they are not too picky about soil or fertilizer. No pruning is needed, but pinching can help with plant shape. They are very pollinator friendly and are beloved by bees and butterflies. 

Zinnias

Zinnias are an old-school favorite in the summer garden. These petal-packed flowers come in every color, with most shades being very bright and intense. They’re also available in a range of sizes, from 1- to 5-foot-tall varieties. Zinnias look beautiful grown in rows as cut flowers (primarily the medium and larger varieties) or they can be scattered throughout the flower garden, which is what we like to do at the farm. 

These pollinator-friendly flowers are very easy to grow from seed directly in the garden. They like to be grown in full sun and aren’t picky about soil as long as it drains well. While pruning isn’t necessary, zinnias do benefit from pinching, which is beneficial for plant shape, size, and flower productions. 

Phlox

Phlox is a perennial that comes back year after year in clumps that fill out and expand. It is a great structure plant that has nice bright green foliage and small blooms that come in various colors, including shades of pink, purple, and white. They don’t make the best cut flowers, but we still have clumps of them scattered throughout the flower garden for their pops of color.

Phlox is typically planted in the garden from 1 gallon size containers, rather than by seed. They come in different sizes, though most are in the medium-tall flower range of 2 to 4 feet. They like full sun but can handle partial shade, and they aren’t picky with fertilizer or soil. No pruning is required, but you should cut off the spent flower heads after they finish blooming.