How to Care For Lavender Grosso

Lavender Grosso ( Lavandula x intermedia) is among the most adaptable lavender hybrids that has merged the hardy characteristics of English lavender with the long blooming time and scent that comes from French lavender.

Lavender grosso key guide:

  • It requires full sun.
  • Most preferably, soils with Alkaline pH (can be grown in soil that has pH 6.5 up to 8.)
  • Only once every two weeks during the growing season.
  • Requires low to medium fertility soil
  • Soil mix must be amended by adding sand or gravel to ensure good drainage
  • Flowers are blooming for about four weeks from mid July through the end of August.
  • Cold-hardy can be found up to USDA zone 5, and is tolerant of frost and snow.
  • Pruning is required once per year, in spring or in late autumn
  • It can reach 46 inches in width and 36 inches tall at the point of full maturity.
  • It thrives in containers, pots as well as raised beds. It is also very well-drained soil for gardening.
  • Grosso is renowned for its aroma and oils and is commercially grown.

Read on for all the details you require to know about how to care and grow lavender Grosso and make sure that the plant will produce the highest quantity of sweet scents and flowers for as long as it is possible…

Where can you Grow Lavender Grosso?

Lavender Grosso is an annual sub-shrub which is an ecstatic mix between French lavenders and English lavenders.

Lavender Grosso is a variety which has been developed to preserve the cold-hardy traits and long-lasting qualities that are characteristic of English lavender (so it is able to be kept in the winter months, while French lavender needs winter protection) and also the longer blooming season and the fine scent that is characteristic of French lavender plant, so you can enjoy all the benefits of both worlds.

This variety is able to thrive in temperate climates that are cool, can withstand frosts, snow and ice in winter . It is considered to be cold-hardy that can be grown to USDA zone 5.

Grosso needs full sunlight, with a well-drained soil, and enjoys a breeze on occasion to help prevent fungal illnesses. It is not able to grow easily in climates that are humid (as as with all varieties of lavender).

lavender with single bee

When Does it Flower?

The exact date of blooming will depend on the weather however lavender Grosso typically blooms in the middle to late summer between July and August, and blooms for a few weeks. Regular deadheading can encourage the blooms to increase.

Pruning in the summer months after flowering can encourage stronger flowers the following year, keep a neat shape and prolong the life of the lavender.

What is The Best Time for Planting?

The best time of year to plant as the lavender enjoys all the growing season of mild weather to allow its roots to develop and grow into the soil. However, this tough variety can be planted during the summer months and in early autumn without difficulty.

Lavenders typically show their best displays of flowers during the time following their planting However, I wrote an article about the steps you can take to reduce the shock of transplants to ensure that your plant blooms the most it can in the first year.

The planting of winter flowers should be avoided since rootstocks will get sown in cold soil when the time of dormancy for lavenders and will be unable to establish themselves.

Care Guide Lavender Grosso

Watering

Lavender that is watered Grosso is low-maintenance when you understand how to water your plant at every stage of its growth.

Lavender is drought-resistant. The plant that has grown in areas with low rainfall and dry soils which is why it doesn’t require regular irrigation.

The reason for problems with lavender care is typically due to the fact that people who garden is frequently watering the plant which causes root decay. The symptoms of stress caused by excessive watering include brown leaves and a look of drooping. (If this happens to your lavender plant, check out my article for the remedy).

When you grow lavender Grosso in a well-draining soil and water the plant every two weeks during the growing season, you’ll avoid the problems that come with excessive watering. The plant will bloom and release scents throughout the year.

Always give your lavender a good soak to allow roots to develop deep into the soil, so that the lavender gets the nutrients and water it requires. Light watering can result in a lower root development which means the plant is less tolerant to drought.

  1. Freshly planted lavender. If you’ve just placed your plant in an perfect location or have recently moved it from one location to another, then the lavender will need more water to settle in its new location. Water Grosso lavender right after planting by giving it a good soak, and then water it every day during the initial week. Following the initial week,, cut down your frequency to one every 3-4 days for the initial three months. After three months, water twice a week during the growing season.
  2. Established lavender. The lavender that has been established (longer than three months) requires water twice a week during the summer and spring months due to its drought-resistant. Don’t be enticed to over water it because a great many issues result from overwatering lavender Grosso than under watering. The lavender that is over watered will appear like it is brown and droopy, and be more susceptible to becoming rot-prone. If there has been a substantial rainfall and you are able to discern moisture up to a finger deep in the soil, then you should not water for a couple of days until the soil is dry before re-watering.
  3. Grosso lavender in containers and pots. In pots, give lavenders an adequate soak to ensure that the water drips from the bottom in the container. It is recommended to water them once every two weeks during the growing season, just as an established lavender. Pots are more likely to dry out in the summer period and when the plant is in scorching sunshine with temperatures that are high however, remember that lavenders are drought-resistant plants that prefer the soil to remain dry in between watering sessions. It is crucial that the pot is minimum 16 inches in size to ensure it can hold enough soil so that the pot doesn’t dry out too fast in the summer, and also provides insulation for the roots in winter. In hot weather , water Grosso can be used to water lavender for 10-14 days, with a an ample soak.
  4. Watering in Winter. Lavender goes into a state of dormancy in winter, and consequently requires less, if any. Lavender Grosso is cold-hardy up to USDA Zone 5 and is able to endure cold temperatures and frost which is why it can be kept outdoors in the majority of cold temperate climates. Lavender can get sufficient water in the soil in winter, if it is left outside and doesn’t require any additional water. The lavenders don’t like being in wet and cold soils during winter. Therefore, make sure the soil drains well and don’t give the plant water until the temperatures begin to warm again in the spring.

Sunlight

Grow lavender Grosso in full sun to get the maximum results. The less sunlight a lavender gets, the lesser flowers it produces therefore, ensure that you place it in the sunniest location within your yard. (For additional tips, read my article on reasons why your lavender doesn’t bloom).

If you’re struggling to find space in your garden , I suggest plant Grosso in pots and choosing an area that is sun-filled instead of trying to find a compromise by planting in partial shade.

The full sun also decreases the risk of fungal diseases and dry any remaining water from rain that could cause issues and ensure the health of the plant.

Optimal Soil for Lavender Grosso

Lavender Grosso is a hybrid of both English and French lavender varieties, and is cultivated to enhance the toughness and durability that are characteristic of English lavender (read my article about hardy English lavenders for more information).

The plant has maintained English lavender’s higher tolerance to slightly acidic soils. It will bloom in soils that have pH ranges from 6.5 up to 7.5 (slightly acidic or alkaline) so it’s better suited to grow in the soil of your garden.

If you live in an acidic area and would like to plant lavender, then check out my article for simple solutions.

Here’s a brief overview of the requirements for lavender grosso soil:

Good drainage, medium to low fertility, and a porous soil structure are the main characteristics of soils in the native Mediterranean home of lavender and are easily replicated within your backyard by amending the soil using gravel or builders sand.

Sand or gravel provides the ideal soil structure to create a soil that is porous which allows water to be able to drain away from lavender roots, which prevents root rot.

Sand or gravel can increase soil fertility. soils since the sand doesn’t contribute nutrients to soils and creates low to moderate fertility conditions that lavender Grosso is a fan of to flourish and to produce the highest yield of oil and flowers, and produce the best scent.

Soil made up of 30 percent sand or gravel and 70 percent organic potting mix (also known as garden soil) is ideal. Include lime in the soil to boost the alkalinity in case you have soil that is acidic. For more information, read my article on the best soil mix for lavenders..

How Far Apart to Plant Grosso Lavender

Lavender Grosso is a large cultivar of lavender that can extend its leaves at full maturity, up at 46inches (116 cm) tall as well as 32 inches (80 centimeters) tall.

It is therefore essential to plant lavender Grosso at least 2 feet apart. This will ensure that each plant gets sufficient air flow and nutrients, as well as water sunlight, and room for roots to grow into the soil.

Lavender Grosso enjoys the airflow (as most lavenders do) around the leaves because it helps lower the risk of fungal diseases and keep the stems and foliage dry and clean, which is the reason why it loves to thrive in a sunny, open space.

Keep in mind that the 2-3 feet of space is also occupied by fences, other plants, walls, and other structures that could hinder the flow of air and shade the lavender.

It is important to note that Grosso grows larger in warmer climates, but remains smaller in colder climates. So you can expect some regional variations based on the location you live in. In any case, it will have plenty of blooms and emit its distinctive scent regardless of its size.

In Pots and Containers

This variety thrives in containers and pots because of their favorable drainage conditions.

It is crucial to select the correct pot for growing Grosso. The pot must be able to drain at the base and be 16 inches in diameter. Do not place the pot on the drip tray or in an ornamental pot that doesn’t allow drainage since the soil will soon get saturated, leading to root decay.

I’ve prepared a guide for selecting the right pot to grow lavenders that will teach you everything you need to know about.

The care of potted lavender Grosso is very like caring for the lavender in your garden They require similar mixture of soil and sunlight, as well as pruning, and irrigation. For more details, take a an interest in my article on taking care of lavender inside pots.

You can cultivate this lavender inside however, due to its an extensive spread when it matures I would suggest smaller varieties such as Lavandula angustifoliaHidcote superior which is smaller at sixteen inches by eight inches (40 centimeters by 45 centimeters) and thus is lighter to be able to fit onto the window sill (all lavenders require the most sun they can get).

Pruning

Pruning lavenders of every kind is vital to maintain the overall appearance and shape, encourages flowering, stops the growth of leggy plants, slows down growth of the base of wood and prolongs the life of your lavender.

If you conduct a thorough search about pruning lavender, you’ll discover some experts in gardening, such as those from the Royal Horticultural Society will suggest cutting lavender in late summer, after the blooms have finished.

Many commercial growers believe that lavenders be cut back early in spring to encourage growth and blooms like this grower from Oregon.

My suggestion to prune the lavender Grosso is that if you live located in a cold climate you should cut the tender green stems back by around a third during the spring to create a lovely round mound.

You can then do an easy pruning to keep the form and maybe harvest the flowers, or cut off any flowers that have faded in the middle of August.

If you live located in a warmer climate and you give your lavender Grosso a hard cut late in the summer, there’s less time for the plant to heal its wounds before winter frost, and it is more prone to being damaged. (Read my article on winter maintenance of the lavender plant).

If you live located in a warmer climate which doesn’t typically see frosts during winter, you can cut back lavender Grosso in late summer or in the early autumn. Grosso is hardy to cold and will not be affected by cold winters in warmer climates.

Do not cut back the woody growth of lavender because it won’t regenerate. Leave at least two inches of greener, softer growth over the brown, woody bottom of the plant. Pruning lavender is similar to the process of pollardinga tree in the sense that the lavender will last for longer, and it will also be better because of it.

Key Takeaways

  • Lavender Grosso is a hybrid of French and English lavender. Grosso keeps the cold-hardy features of English lavenders as well as the longer blooming time of French lavenders.
  • The ideal moment to start planting is in spring, when the temperature has risen however this tough variety is able to be planted until the beginning of autumn. Plant in full sun to get the optimal results.
  • Lavender Grosso is cold hardy up to USDA zone 5, and is able to endure winter temperatures, frosts and snow.
  • Grosso is a more extensive type of lavender that is in a width of 46 inches and inches tall. To get the best results, plant it 2-3 feet away from other plants or lavenders to allow for airflow and to make sure that the other plants do not cast shade, which can reduce the blooms.
  • Grosso is drought-resistant and requires only watering once every two weeks once it has established.
  • Pruning is essential every year to keep the appearance of the plant, encourage flowers, and prolong the lifespan of the lavender.
  • The soil must be well-drained, between pH 6.5-8 moderate to low fertility, and an open structure. This is possible by amending soil using limestone or sand, and also lime in the case that your garden soil is especially acidic.
Stephanie

Stephanie

Went from a bad gardener to a half-decent one over 10+ years. Super happy to share my tips and tricks with you :)