June is the month to enjoy the fruits of your labor. All the time you spent weeding, pruning and encouraging your plants will pay off, and your flower beds will burst with color and fragrance. There is still much to do in the garden, but above all, we encourage you to take a little time to savor the bounty of early summer.
Now, it's time to rest. June is the perfect time to sow biennial seeds. For those of you wondering what biennials are, a quick explanation is that they are plants that have a two-year cycle. If you sow biennial seeds this month, they can germinate and grow by the end of summer. Throughout the fall and winter, biennial plants go into a dormant state before growing and blooming the following year. This may seem like a long process, but with a little effort now, you can be sure of an abundance of beautiful flowers next year.
So if you're thinking about what to plant in June, I recommend adding one or two biennials to your sowing list. Here are my favourite biennials to plant this month, all of which I've sown and grown in both the historic English gardens and the Italian country villa gardens where I've worked.
(Image courtesy of Future/Jacky Hobbs)
Biennials to plant in June
June is a busy month for the garden, with many tasks on the summer gardening checklist, including watering, fertilizing, and choosing perennials to plant in June.
This month is an ideal time to sow biennial seeds; your future self will thank you! Sow biennial seeds in trays or modules and place them in a greenhouse, cold frame or windowsill. We recommend using reusable seed-starting trays, available at Walmart, so your seeds have the best chance of growing and can be reused for sowing next year.
1. Digitalis
(Image courtesy of Future/Jacky Hobbs)
Foxgloves make a striking addition to the spring garden, with vertical flower spikes that can reach heights of up to 5 ft. When considering how to grow foxgloves, this biennial plant can be sown to seed in June and the tiny seedlings planted in the garden in late August or September.
In my experience, the longer you can leave biennials in your flower bed before winter sets in, the more likely they are to be successful. The more time they have to establish before the cold weather hits, the better the results.
Foxgloves are considered one of the best native flowers, so if you're wondering what to do with your foxglove after it blooms, leave the dead stems so they can produce seeds.
You may already have foxgloves growing in your garden so why not try collecting the seeds and sowing them in trays this month. Sow the seeds thinly – this will improve germination and growth if the seedlings have enough space to grow.
You can buy foxglove seeds online from Walmart.
2. Arctic poppy
(Image credit: Getty Images/Gerald Corsi)
An unusual biennial, but certainly one of my favorites, the Arctic poppy (Papaver radicatum) produces delicate lemon-yellow flowers.
Native to the high mountain regions of Europe, North America and Asia, the Arctic poppy is one of the northernmost flowers in the world.
When considering how to grow poppies, this species is similar to most other poppies in that it prefers dry, rocky ground, making it a good plant to have if you're looking for gravel garden ideas. It's a frost- and cold-tolerant plant, so gardeners in the cooler hardiness zones of the United States should consider planting this biennial in their gardens.
Seed Starter Tray – Plant Germination Kit
This seed sowing kit is ideal for all gardeners and will help you to have a successful sowing activity.This kit is perfect for sowing and germinating seeds, easy and convenient to operate.
3. Honesty
(Image courtesy of Getty Images/Federica Grassi)
Honesty (Lunaria annua) is one of the most popular cottage garden plants, known for its long flowering season. Honesty is also prized for its translucent-looking seed pods, which are often used by florists in dried flower displays.
This biennial is a great plant to add to your sowing list in June, giving the seedlings plenty of time to grow and establish before winter sets in. These plants will produce flowers in shades of purple or white the following spring, depending on the variety you grow.
One of my favourite varieties is Lunaria annua 'Corfu Blue', which produces deep purple flowers that make a striking addition to any flower bed. Honesty Seeds is available from Burpee.
4. Smyrnium
(Image credit: Getty Images/Wirestock)
If you're looking for flower bed ideas this year, Smyrnium perfoliatum is an unusual, vibrant plant that produces lime green flowers in spring and summer.
I've grown this hardy native plant in partial shade before, but it grew so quickly that I often had to thin it out every few years. Sow smyrnium seeds this month and you'll be greeted with a profusion of lime green flowers next year that will blend well with woodland plants like ferns and hostas.
If you don't have a greenhouse, don't worry: seed starting kits available at Walmart are a good alternative and can be placed in a bright spot in your kitchen.
5. Forget-me-nots
(Image credit: Getty Images/mikroman6)
If you're looking for cottage garden ideas, forget-me-nots are a great plant to plant along paths and patio edges. This biennial plant is self-growing, so once you have a few in your garden, they will come back year after year, often growing under shrubs and trees.
Flowering from spring to early summer, these biennials make great supporting plants in garden borders, complementing spring displays of tulips and daffodils. Of all the blue flowers, few are easier to grow than forget-me-nots.
Bags of forget-me-not seeds can be purchased online from Walmart.
Burpee Indoor Seed Starter Kit
This handy growing set includes two seed starting trays and one water storage tray, making it an easy and efficient way to start seeds indoors.
6. Icelandic poppy
(Image credit: Adam Yee/Shutterstock)
There are many different types of poppies, but the Iceland poppy (Papaver nudicaule) is a stunning flower that can be grown in a variety of colors.
I find poppies are a little more difficult to transplant than other seedlings, so I like to germinate the seeds in biodegradable pots like these ones sold on Amazon, which can be planted directly in the garden without damaging the roots.
These poppies prefer an open, sunny spot in the garden and well-drained soil. When planted in the right location, these poppies will bloom from May through September. You can order Iceland poppy seeds online from Walmart.
Like other poppies, this species is self-growing, so leave the withered flowers to allow seeds to be produced and dispersed.
7. The Wallflowers
(Image credit: Getty Images/ANA LEBIODIENE)
Wallflowers require full sun and well-drained soil. They usually flower for a long period during the growing season and are known to be popular pollinator plants.
Plus, there's a wide range of cultivars to choose from, with blooms in a variety of colors, like 'Bowl's Mauve', which has blue-purple flowers, or 'Night Skies', which has dark brown and yellow blooms.
Transplant seedlings into the edges of your garden in late summer. Pinch off the growing tips at this stage to encourage bushy, compact growth. English Wallflower seeds are available at Walmart.
FAQ
Do I need a greenhouse to sow biennial seeds?
No, you don't need a greenhouse to grow biennial seeds. Place the seed trays on a windowsill or in a bright spot indoors, monitor the soil conditions, and water as needed. Once the seedlings are a manageable size, plant them out in individual containers and move them to a protected spot outdoors later in the season.
June is a busy month for gardeners, but taking a little time to sow biennial seeds can ensure next year's blooms are better than ever. For gardening information on what to do this month, check out our guide to vegetables to plant in June.
