How to Grow Heliotrope

Colorful and aromatic, the heliotrope has long been a staple of the ornamental flower garden. Also known as White Queen, Cherry Pie and Mary Fox, Heliotrope (Heliotropium arborescens) is currently enjoying a resurgence in popularity.

An old fashioned favorite, heliotrope is enjoying a resurgence in popularity.

Originating in Peru, the name heliotrope is derived from the Greek words helios, meaning sun, and torpos, meaning turn. The name reflects the flower’s habit of following the sun across the sky.

Suitable for cultivation in most gardens, the plant’s dense cluster of vanilla or cherry scented blooms are particularly abundant if grown in hot and dry conditions. Usually cultivated as an annual plant these are, in fact, temperate perennials.

Reaching a height of 1 to 4 ft depending on the growing conditions these are small, shrub-like plants. Known for their elongated oval shaped dark green foliage the flowers bloom from early in summer and last until the first frost. Whilst in bloom the flowers attract scores of pollinators such as butterflies to the garden.

In addition to the traditional deep purple flowering plants, varieties in paler shades of lavender and white are also available. While the newer cultivars are just as attractive, many growers still prefer the older purple varieties because these tend to be hardier and more resilient than newer cultivars. Older cultivars also have a more noticeable fragrance.

Despite being an old fashioned favorite, in recent years increasing numbers of garden stores and nurseries have begun to sell this attractive flower. If you want to add heliotrope to your garden, this is everything that you need to know.

Warning these plants are poisonous to both animals and humans if ingested.

Different Heliotrope Varieties

There are a number of different heliotrope varieties available. Most garden stores and plant nurseries sell heliotrope either as seeds or as young plants. While purchasing young plants is often easier, all you need to do is plant them out, seeds are often cheaper and allow you access to a wider variety of flowers.

One of the most commonly grown is Fragrant Delight. This is an aromatic vanilla scented cultivar. It’s pretty violet flowers sit on elegant stems above the plant’s dark green foliage.

White heliotrope is a reliable cultivar that is grown partly for its almond fragrance. A long lasting plant, as the name suggests it produces white flowers throughout the summer months until the first frost hits.

Amaretto is an old fashioned favorite which produces attractive purple or lilac flowers. Its flowers, and almond aroma, are sure to attract butterflies and pollinators to your garden.

As well as the common purple cultivars, you can now also find pale lilac and white varieties. 

Marine is another common cultivar. A reliable plant it is grown for both its purple flowers and sweet fragrance.

Dwarf Marine is a popular dwarf variety, hardy in USDA zones 9 to 11. It produces masses of green foliage and deep violet flowers. Reaching a height of 12 to 19 inches it is pleasingly disease resistant.

How to Grow From Seed

Heliotrope plants are easily started from seed.

Sow your chosen seeds undercover in trays or pots filled with fresh potting soil 10 to 12 weeks before your last predicted frost date.

Scatter the seeds thinly on the soil and cover lightly with fresh potting soil.

Ideally seeds need a temperature range of 70 to 75 ℉ to germinate. This can take 4 to 6 weeks depending on the conditions.

Once the last frost has passed and the soil is at least 60 ℉ harden off your seedlings before transplanting into their final position.

Starting seeds off undercover, and growing on until the last frost, enables you to get a head start on your spring and summer flowers. 

Where to Plant

Heliotrope flowers do best in light positions. They should receive at least 6 hours of sunlight every day.  If you are growing in a warm climate, plant somewhere where the flowers can receive some afternoon shade.

These flowers do best in rich or loamy soil. They struggle in heavy clay type soils. There are a number of ways to improve heavy clay soil, enabling you to plant a wider range of flowers. Use a soil test kit if you are unsure of the makeup of your soil. The soil should have a pH reading of between 6.6 and 7.3.

A sun loving plant, make sure that there is some afternoon shade. 

Transplanting Flowers

Weed the soil well before planting. Remember that the soil should be at least 60 ℉ before you begin planting.

Dig a hole in the soil large enough to hold the container that the plant is currently growing in. When placed in the hole the plant should sit at the same level as in the pot.

Carefully remove the plant from the pot, squeezing the sides to loosen the soil. Place the plant in the hole and backfill carefully. Firm down the soil, but don’t compact it. Water the flower well.

If you are planting more than one flower, space them about 11 inches apart. This may seem a lot but as the plants grow they become bushier and fuller. Rows of heliotrope should also be spaced at least 11 inches apart.

Can I Grow Heliotrope in a Container?

These attractive flowers are ideal for container gardens. They are pleasingly robust and are not susceptible to pests or diseases such as powdery mildew. They are also not invasive and are unlikely to overpower and smother other flowers planted in the same container.

Your chosen pot should have drainage holes in the bottom. These flowers dislike sitting in overly wet or soggy soil.

Fill your pot or pots with a rich, well-draining potting mix. A fresh general purpose potting mix with some organic matter, such as compost, worked in is ideal.  Alternatively, you can mix a handful or two of sand into your general purpose potting mix. This helps to improve drainage.

Plant as described above.

Caring for Heliotrope Flowers

Once planted, heliotrope care is pleasingly straightforward.

Keep the soil around the plants as weed free as possible. Quick growing weeds can harvest moisture and nutrients from the soil, stunting the growth of your flowers.

When to Water

Keep the soil evenly moist. Don’t let it dry out.

While the soil should never be allowed to dry out, it also shouldn’t be allowed to become overly wet or soggy. This balance can be difficult to achieve, particularly in pots.

A soil moisture meter, such as the Gouevn Moisture Meter, allows you to accurately monitor the moisture content of your soil. This makes knowing when to water your plants a lot easier.

Fertilizing your Flowers

Fertilize your plants regularly. Heliotrope is a heavy feeding plant. If planted in the ground they require an application of a well balanced or phosphorus rich liquid fertilizer once every two weeks. Phosphorus rich fertilizers encourage more flowers to form.

Avoid feeding your plants nitrogen heavy fertilizers. These encourage leaf production at the expense of flowering.

Plants in containers may require more regular fertilizing.

Pinching Out and Pruning

Begin pinching out the plants when they are still young. This encourages them to become bushier. While pinching out can delay flowering, when flowers do emerge you will have a fuller, longer lasting display.

Pinching out plants, particularly when they are young, helps to create a bushier plant. It also encourages more flowers to form. 

Deadhead spent flowers to prolong the flowering period.

Winter Care

Perennial in USDA Zones 10 and 11 the heliotrope is usually grown as an annual.

If you want to keep the plant for next year you will need to protect it from winter frosts. While many people choose to keep their flowers overwinter, the older the plant gets the leggier it will become.

In milder USDA zones plants in the ground can be protected from light frosts by a horticultural blanket. The Kupton Plant Cover protects garden plants from frosts and cold weather while still enabling light and moisture to permeate through to the soil and root system.

Growing in pots on wheeled caddies makes overwintering remarkably easy. The Amagabeli Plant Caddy is a durable caddy that allows you to easily move large pots around your home or garden. Simply move the pots inside when the first frost date approaches.

Heliotrope, as well as being a colourful bedding plant, is also a great houseplant. To keep the plant indoors, cut the plant back to about half its size and repot it in a rich, houseplant or general purpose potting soil. Place the plant in a warm place, such as a bright windowsill and water well.

Alternatively repot in the sprIng, as the weather begins to warm up. This is the preferred option if you want to return the flowers to their outside position.

Whenever you choose to repot, be careful not to overly disturb the root system. This can send the plant into shock, causing leaf drop.

If you don’t want to overwinter the entire plant, take cuttings in late summer and root them overwinter. These can then be planted out the following spring.

Propagation

While growing from seed is possible, taking cuttings is a more common method of propagation.

Propagation by cuttings ensures that your new plants are true to the parent plant. Seeds gathered from hybrid plants do not produce flowers that are true to the parent. This method of propagation also produces sturdier plants than those grown from seed.

Pinching back your plant as it grows helps to create stems more suitable for cuttings.

The best time to take cuttings is in late summer, just as the plant begins to get leggy. Each cutting should be about 5 inches long. Aim to make the cut just below a leaf node, this is a bump in the stem.

Remove any foliage from the lower half of the cutting and dip the cut stem in rooting hormone. Rooting hormone is not necessary for this process to be successful, but it does help to encourage root production.

Plant the cutting in a small pot filled with fresh potting soil. You can also root cuttings in an even mix of perlite and sand.

Place the pot in a sheltered position such as in a greenhouse and keep the soil moist. Roots should form within two weeks.

Allow the cutting to continue growing over winter. During this period keep the soil moist but not waterlogged.

The cuttings can be hardened off and transplanted outside once the last frost has passed.

Common Problems and How to Solve Them

If properly cared for, these are pleasingly problem free plants.

Be careful when watering not to overwater the plant. Soggy or waterlogged soil can cause mildew amongst other issues.

Foliage turning brown and falling from the plant can be a sign that the plant is sitting in soil that is too wet. If this issue occurs, allow the soil to fully dry out before watering again. When you do resume watering, apply less water than previously.

Regularly inspect your plants for signs of infestation. Common heliotrope pests include white flies, spider mites, mealy bugs and aphids. Infestations can be removed with a blast from a hosepipe or an application of insecticidal soap.

Bright and cheerful, the heliotrope brings color and pollinators to your garden. They are also pleasingly easy to care for.

A popular pollinator plant, heliotrope is ideal for mixed beds and edging as well as pots and window boxes. Despite being an attractive ornamental plant it is not a common choice as a companion plant. Nevertheless heliotrope works particularly well with other fragrant flowers such as Nicotiana. Cineraria, Lobelia and Alyssum are also popular combinations as are geranium, gerbera daisy, hydrangea and stock.

An old world favorite that is rightly enjoying a renaissance, the heliotrope is a charming addition to any garden or plant collection.