I’m so excited because my English lavender is starting to bloom right now! Soon my garden will fill with its intoxicating fragrance, generous flower spikes and loads of bee, butterflies and other pollinators! If you too have this magical shrub in your garden, then you know what I man, but…
Many amateur gardeners have told me that their lavender shrubs only bloom for about one month, at least big time, sometimes even less, then they “become lazy” or they stop altogether.
This means that they are doing something wrong, because lavender should bloom for about two months, from June to July (in temperate regions, it can start later in colder climates – so, don’t worry if this is your case), and from May to June in warm, especially Mediterranean regions where it comes from.
In the right climate, and if you treat it well, it can give you an “encore” later on in early fall, with another floral display.
Actually, I am talking about English lavender here (Lavandula angustifolia), the most common and fragrant species or “variety”, the one we use for perfume.
Lavandin (Lavandula x intermedia) is also very common, and it blooms from June to July, so, if you are growing this hybrid, you should be seeing the first flowers by now.
If you are growing small Spanish lavender (Lavandula stoechas), withiest big, butterfly-looking-like blooms, then it flowers in May and June, but then again in fall.
If instead your shrub is French lavender (Lavandula dentata), with fringed leaves, then you are growing a marathon bloomer, which flowers from May to October in waves and with short pauses.
Whichever the variety (or varieties) you have in your garden, if you want to have generous and long-lasting blooms, I have some tips for you and some mistakes to avoid. Let’s talk about them!
1. Deadhead Early Lavender Flowers
This is very important; if you leave the dried spikes on, your lavender will not producing many more- maybe aa few, but it will disappoint you. The reason is simple; it will concentrate its energy on growing seeds.
Now, lavender flowers are a bit weird; if you pick them, they will keep their lovely color, but if you leave them on the branches, they will become grayish brownish… You don’t want your fragrant blossoms to reach that stage, because you want to keep them for their amazing scent (English lavender especially) or to make soap (lavandin).
So, let me tell you the secret of how lavender experts harvest the spikes while they are still colorful and at the peak of their fragrance:
Check the base of the spike for color shifts (fading from bright purple to a muted grey-green).
Check the and firmness at the base of the spike as well; gently run your fingers down the stem just below the flower head. If the stem feels woody and firm rather than green and pliable, the spike is fully mature.
Use the “pinch test”: give the flowers a gentle squeeze. If they feel firm and look fully colored, they are in their prime. If they feel papery and easily crumble, the spike has dried past its peak.
Finally, make sure that at least the lowest 2 rows of florets have opened. Yes, you can pick them quite early if you want to harvest them for their fragrance; this is actually when lavender has its most powerful scent – don’t worry; it will grow new buds and blooms soon.
Use a sharp, sterile knife or scissors to deadhead lavender; the stems are very sturdy, and it’s hard to pinch them without ruining them.
2. Absolutely do NOT Overwater Lavender!
“Great, my lavender is about to bloom – it must be thirsty!” Big mistake! No, Lavandula does not need any water when it is flowering. In fact, if you overwater it, you run a few risks…
To start with, the blooms will be less fragrant; the essential oils of lavender depend on the concentration of linalool and linalyl acetate (two substances it produces) and other compounds in the flowers. If you fill them with water, you reduce the intensity of the scent.
But there’s even a bigger danger; lavender likes dry soil – always! If you overwater it, you risk giving it health problems, like molds, fungi and – the scariest of all, root rot, which may spell the death of your perfumed flowering shrub.
Always wait till the soil is completely dry before watering lavender. If you forget to irrigate it for a few days (even weeks) it will still survive and bloom healthily.
3. Clean and Tidy up the Bottom of the Lavender Shrub
On a related topic, check if your lavender shrub has a very dense lower part. The bottom branches will not bloom, so and you want your scented queen to focus her energy on the flowering spikes at the top.
What’s more, the lower branches tend to collect humidity, and they aren’t great for ventilation. Spring has just come to an end, with its abundant rains, and they may have caught diseases or pathogens (molds, fungi etc.) So, this is the ideal time to prune them off.
Make sure that the first branch for English, French or lavender and lavandin are at least 2 to 3 inches (5.0 to 7.5 cm) from the ground. Lavandula stoechas, the Spanish variety has a more upright habit and it is smaller, so you can be more relaxed with it (still, 1 inch or 2.5 cm can help).
However…
4. Delay Major Pruning
At this stage, all you need to do is deadhead the flowering spikes and keep the base clean, tidy and well ventilated. Don’t be tempted to go down heavily on your lavender shrubs now, nor to shape it or keep it into shape.
If you do, you’ll end up cutting all the new stems that are about to grow new buds and blossoms.
You should only prune lavender after it has fully finished blooming, so, in late summer for most varieties (late fall for French lavender, or Lavandula dentata).
Actually, if you prune English lavender after it has finished flowering and the weather, climate and conditions are right, it may reward you with a gift: a second wave of fragrant blooms later in the season. It is usually smaller than the spring/summer one, but still…
5. Don’t Use High Nitrogen Fertilizers!
In this season, you need to understand what your lavender wants to do and help her along. If you use a fertilizer high in nitrogen, you will go against its natural life cycle.
When lavender starts producing the first buds, and throughout the blooming season(s) it doesn’t want to grow new shoots and leaves – and nitrogen does just that.
Instead, you need to give your lavender fertilizers that are rich in phosphorus (the “P” in “NPK”). This nutrient promotes flowers and fruiting.
So, I suggest natural fast-release (liquid) fertilizers with NPK of around 5-10-10, 4-8-8, or 3-7-7. Mix it with water (1 part to 10) when you irrigate and only use half the dosage but often (every two weeks).
However, if you are growing your lavender in containers, they lose nutrients more quickly, so do it every week in this case.
When the blooms are peaking, suspend fertilizing your lavender (it’s fine now, don’t encourage your shrub to “get distracted” by growing new spikes), and start again when the flowering is diminishing.
Also use a natural slow release, granular fertilizer with NPK around 5-10-10 or 4-6-8, only once and when you see the first buds. If you haven’t yet, do it now, even if the flowers are opening.
You can also use some natural supplements to sustain your lavender’s blooming season, like:
- Bone meal, with a typical NPK of 3-15-0, it is a slow-release fertilizer that promotes massive blooms (and it also helps your lavender grow roots). Use 2 to 4 tablespoons (40 to 80 grams) once.
- Rock phosphate; rich in phosphorus, it is very slow release and it can last for years! You only need 2 to 4 tablespoons (40 to 80 grams) every 2 to 3 years.
- Wood ash is rich in potassium and calcium as well as lots of trace nutrients; these are like “vitamins” for your lavender. It won’t promote blooms, but it will keep your shrubs and their spikes healthy. Apply 1 to 2 tablespoons (20 to 30 grams) at the beginning of the blooming season (then again in early spring).
- Greensand; it has very low nitrogen and phosphorus, but a whopping 5 to 10% potassium! What’s more, it improves the drought tolerance of plants – excellent for the dry summer season… Use ¼ to ½ cup (50 to 100 grams) only once at the beginning of the blooming season.
- Seaweed meal; this is another “medicine” for your lavender; it has lots of trace elements and growth hormones, and it helps your lavender (and other plants) overcome stress. You will need 1 or 2 tablespoons (20 to 40 grams) at the beginning of summer.
- Kelp liquid is instead a fast-release fertilizer and it is super rich in trace elements (very poor in NPK), so, a medicine. Dilute it (1 to 10) in water and use it every time you irrigate (or 5 to 10 but every 4 to 6 weeks).
Of course, some worm castings are always welcome!
6. Protect Your Lavender from Excessive Rain
If you live in Arizona, California or Nevada etc., skip this section. But if you are growing lavender in Florida, Louisiana, Mississippi, Texas, and Georgia, or any other states with humid summers, or you expect lots of rain in this season, you will have to protect your fragrant flowering shrubs from excessive rainfall.
First of all, rain is not too dangerous overground, as long as you have properly cleaned and tidies up the bottom of your lavender shrubs (see “Section 3” above). The problem is when water pockets form in the ground; they can cause rot to the roots of your shrubs.
“How do I go about it,” I can hear you ask? It depends on how well drained your soil is.
Let’s start with the “lucky option”… If you have sand-based soil, you won’t need to do anything – drainage is already excellent.
If your soil is predominantly loam (humus), clay or chalk (lime), then the chances are that you will have to improve its drainage.
Be flexible; you may already have good drainage, so I will give you the maximum levels of “soil improvement” but first…
If your soil is mainly loam, it’s not really bad news… You need 2 to 4 inches (or 5.0 to 10 cm) of coarse sand or horticultural grit all around the base of the plant (16 inches or 40 cm in radius). You can mix it in with the top soi, but also just put a layer and the rain will push it underground (humus is very permeable).
The issue gets more complex with heavy chalk… You will need to incorporate grit (2 to 3 inches or 5.0 to 7.5 cm) into the top soil, as it won’t penetrate otherwise. Use the same 16-inch radius (40 cm) rule, and make sure you do not damage the roots. Finally, I also suggest you add some coarse sand afterwards; now it can go underground, 4 to 8 inches (5.0 to 10 cm).
If you are growing lavender in heavy clay, sand and grit are useless. You will have to use gypsum (don’t worry it’s cheap). Using the same 16-inch radius as before (40 cm), lay 4 to 6 inches (10 to 16 cm) and then incorporate it into the topsoil – again, do not damage the roots!
In all cases, use what we call gravel mulch; you need to build a mound (1 to 2 inches high, or 2.5 to 5.0 cm) all around each shrub about 32 inches in diameter (80 cm), or 16 inches on each side of the base of the shrub (40 cm). You can use gravel, crushed stone, lava rock, or grit for this and remember to leave a gap between it and the woody base of the shrub.
Finally, if you are growing lavender in containers, on top of improving drainage, remove the saucers. They collect stagnant water.
Encourage Pollinators
…Or rather, don’t discourage them… Lavender attracts hordes of them, but the best winged friends of your garden come to eat…
So, always allow some of the florets on the spikes to open, at least the first two bottom rows before you deadhead and / or harvest the spikes.
Enjoy Your Lavender Blooms!
All you have left to do now is enjoy that miracle of nature which is blooming lavender; do it with your eyes, your nostrils, your whole relaxed body and your heart.
