When deciding which flowers to plant in August, you have a little more leeway than in July as we move toward the cooler, wetter days of fall. However, the soil may still be dry after the hot summer and your beds and borders are probably still full of plants. That means you’re spoiled for choice, as hardy annuals, biennials and perennials can be sown in trays now. However, you shouldn’t sow semi-hardy annuals until April or early May next year, when temperatures start to rise again. Follow these tips on which flowers to plant in August, and you’ll have a lush garden.
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What flowers you should plant in August
Top plants to grow in late summer – lupines.
Lupines are a staple in the cottage garden, reliable bloomers with dense towers of flowers in pink, purple, blue, red, yellow and cream. They usually decorate the center and back of beds, but you can also buy dwarf varieties like “Pixie Delight” that provide color in the front of beds and do well in containers (watch out for aphids, though). Lupines are hardy annuals and belong to the pea family. They develop long taproots and a strong root system. Therefore, sow them directly into the ground where they can root deeply and become well established.
They like a sunny place and a fertile soil. Therefore, add plenty of well-rotted compost or manure before sowing. Keep the soil well watered while the seeds germinate, and thin the seedlings at close intervals.
Top tip: If you don’t have room to sow seeds outdoors or your soil is still too hard and dry, sow your lupins in deep pots and modules. Care for them over the winter in a greenhouse and plant them out next spring when the soil warms up.
Silverleaf does best in alkaline soils
Silverleaf (Lunaria annua) is one of the most recognizable plants. A vigorous biennial in the cabbage family, it forms large flower clusters that detach from pretty, delicate, flattened seed pods. The flowers are usually pink or white, although some varieties form a mixture of both. Because silverleaf is a biennial, it forms its first leaves this year and continues to grow and bloom the next spring before forming seeds and dying. Silverleaf does best in alkaline soils and likes to self-seed. This creates colorful clumps in the summer and an interesting plant in the winter if you leave the seed pods.
Top tip: If you decide to sow Honesty’s seeds in modules, plant them out before they get too big. Like all brassicas, they develop a strong taproot and don’t do as well if the roots don’t have enough room to develop properly.
What vegetables to sow in August? You can read about it here !
Nigella blooms for a long time & is easy to grow
Nigella, also known as love in the mist, is a traditional garden plant that comes in a variety of colors, from light blue to midnight indigo to deep maroon. It is a hardy annual flower that is easy to grow, blooms for a long time, and has attractive seed heads that are suitable for indoor arrangements. You can sow them now or wait until spring, though those sown in the fall usually bloom earlier and better. So if you’re wondering what to plant in August, these plants are a good choice.
Scatter the seeds thinly in fertile, well-drained soil in a sunny spot, then cover with more soil. Water the seeds with a watering can with a fine rose attached, and mark the area so you don’t disturb the seeds while gardening. Once the seeds germinate and are large enough to work with, thin them out and protect them from pests. Keep the soil moist and they will put on a great show next year from May into early fall.
Top tip: Nigella is so easy to care for, it’s called ‘sow and forget’. It will happily self-seed and form pretty clusters of flowers in the garden. The seeds are large and easy to collect, so you can also sow them wherever you like.
What flowers you should plant in August – dahlias.
‘Bishop’s Children’ dahlias are a showy variety in shades from deep pink to burnt orange over striking dark foliage. Delicious dahlias are one of the most diverse and longest-blooming perennials, guaranteeing you color and interesting foliage from midsummer deep into fall. And August is a great time to plant them out. All dahlia species are known for their glossy petals in a variety of dazzling colors, as well as their wide range of shapes and styles, from small pompons to plate-sized blooms.
An added bonus is that dahlias are just as comfortable in your container garden as they are in the ground, as long as they are well cared for and watered. If you grow your plants in containers, you can more easily move them to a greenhouse or porch in the winter when the top growth dies back and the tubers need to be stored in a tray of compost in a frost-free area.
Crocosmia (Montbretia) is a late summer plant with fiery flowers.
Native to South Africa, Crocosmia, also known as Montbretia, form their glossy, drooping flower clusters above tall, elegant, strap-shaped leaves that take up very little space, so you can plant many complementary things around them. They can become invasive as they mature and the tubers they grow from multiply. Solve this problem by digging them up and dividing the tubers. Keep the young, firm tubers and discard the old or soft, squishy tubers that feel.
Top tip: Because they are native to the southern hemisphere, Crocosmia are not reliably hardy in northern and exposed gardens. Therefore, they need to be mulched with a generous layer of well-rotted compost or manure in late fall when their leaves have died.
What else can you plant in August – vegetables, flowers and balcony plants? Find out here !