Rosemary is a Mediterranean plant that works well in full sun, sandy soil with good drainage, and doesn’t require a lot of water.
Overwatering and poorly draining soils are the main causes of rosemary death because they foster the growth of root rot infections, which cause the leaves to become brown and wither. In excess shadow, rosemary turns yellow and appears to be dying.
The most frequent causes of rosemary dying are listed here in brief:
|Causes of Rosemary’s Death
|(1) Overwatering (drooping appearance with brown leaves).
|Rosemary can withstand droughts and prefers sandy soils with rapid drainage. Too much moisture around the roots from overwatering results in root rot.
|2. Slow soil drainage
|In stony, steep soil, rosemary flourishes. Root rot results from excessive soil moisture retention or naturally wet conditions.
|3. Insufficient sunshine.
|Rosemary can thrive in broad sunlight. The rosemary frequently dies back with yellowing foliage when it is in too much shade.
|4. The soil is very acidic.
|The pH range for rosemary is 6-7.5. The rosemary will turn yellow and wither if the soil is too acidic because the roots cannot absorb the nutrients they require.
|5. The incorrect climate for rosemary
|Rosemary loves warm winters but is vulnerable to frost damage in harsh winters and is frequently killed by root rot brought on by cold, damp soils.
|6. The humidity is too high for rosemary.
|On hillsides with plenty of airflow, rosemary grows spontaneously. In addition to slowing evaporation, excessive humidity also raises the danger of fungal infections like root rot.
|7. Rosemary can die from severe pruning.
|Lavender and rosemary dislike having their old wood cut away since that wood doesn’t regenerate and produce new stems. The rosemary plant should only have its top third cut.
|8. Rosemary will become yellow and droopy with too much fertilizer.
|Rosemary can thrive on sandier, medium-to-low fertile soils. When there is too much growth and too much nitrogen in the soil from fertilizer, the stems become droopy and yellow and more susceptible to pests and disease.
Continue reading to find out the causes of your rosemary’s demise and how to put the answers into practice to save it.
Table of Contents
1. Over Watering Rosemary (Drooping Appearance with Yellow or Brown Leaves)
Overwatering is the most frequent cause of rosemary death. The herb rosemary is drought-resistant and favors drier environments. Overwatering results in moist circumstances that encourage root rot, which causes the rosemary to wilt and become brown.
Rosemary is a native of Europe’s Mediterranean region, where it thrives in the hot summer sun, sandy soils (which quickly dry out), and infrequent rainfall.
To stay healthy, flourish, and produce its potent and distinctively fragrance leaves for cooking, rosemary just needs occasional watering.
Due of the rosemary’s drought resilience, gardeners should only water it during very severe droughts after the first year of planting because rosemary is particularly sensitive to the effects of overwatering.
If planted in raised beds or garden borders, established rosemary plants in temperate areas frequently don’t require any additional watering at all because they may get all the moisture they need from rainfall, even during the drier Summer months.
Since pots tend to dry out much more quickly in the summer (especially since rosemary enjoys full light), watering once every two weeks is frequently acceptable. You are overwatering rosemary if you give your plants more frequent waterings than once every two weeks.
When rosemary is often watered, the roots’ capacity to absorb moisture and nutrients is hampered. Depending on the degree of the overwatering, this might cause the rosemary leaves to turn yellow or brown.
A significant factor in rosemary turning dark or black, drooping, and dying back is the presence of fungus disease pathogens such root rot and Botrytis, both of which flourish in moist soil conditions.
As a result, when it comes to rosemary dying, overwatering is almost often the issue rather than underwatering. Keep in mind that rosemary (along with other Mediterranean herbs) has the ability to endure dryness in some of the hottest and driest places of Europe.
How to Save Overwatered Rosemary…
If your rosemary is exhibiting signs of stress due to overwatering, stop watering right away and, if you can, relocate potted rosemary under shelter if heavy rain is predicted in your region. This will allow the rosemary’s roots time to dry out and a chance to recuperate.
For reference, the following table shows how frequently rosemary should be watered:
|Prerequisites for Lavender
|When Should I Water My Lavender?
|new rosemary plants:
|For the first four weeks, drink water once a week.
|In the first year following planting, rosemary:
|If there is little or no rainfall during this time, water once every two weeks (during the spring and summer) with a generous soak to encourage the roots to take root.
|Established rosemary (planted more than a year ago):
|Unless there has been a noticeable drought for several weeks, no irrigation is necessary.
|Marigolds in pots:
|During the summer, water once every two weeks with a good soak (if there hasn’t been much rain).
|In the Winter:
|In the winter, rosemary goes dormant and doesn’t need irrigation.
Most rosemary plants don’t need to be watered because it is drought-resistant, but rosemary in pots may need to be watered on a schedule because there are some factors that can speed up how quickly the soil dries out. I wrote another article outlining the best methods for watering rosemary in pots in various climates and conditions.
Rosemary with Root Rot: Saving it…
It’s crucial to look at the roots of rosemary to see whether it has root rot. The roots of a healthy rosemary plant should be light brown, solid, and smellless.
Root rot causes darker brown, mushy, rotten-looking, and foul-smelling rosemary roots.
- With a clean pair of pruners, cut any unhealthy, diseased roots back to promote healthy growth. To stop the transmission of fungi from bad roots to otherwise healthy roots, wipe the pruner blades with a towel dipped in alcohol disinfectant.
- Replant the rosemary in a new container with soil that is around 70% peat-free multipurpose compost and 30% sand to encourage adequate drainage.
- If you are growing rosemary in a pot, dispose of the old dirt and disinfect the pot after washing it out. The old soil may have fungi that can destroy the rosemary.
- Give the pot a thorough soak after replanting the rosemary, then set it in some shade to help it recuperate.
If the unhealthy roots are not cut back, the fungal infection spreads and the rosemary dies.
The rosemary may die back if there is widespread root rot because there may not be enough healthy, viable roots left, but by removing the diseased roots, you are giving the rosemary the best chance of recovery.
Since rosemary has evolved to thrive in sandy, rocky soil and slow-draining soils create the same symptoms as overwatering rosemary, you should also take this into account.
2. Soil Drains Too Slowly
If rosemary plants are in soil that drains slowly or retains too much moisture, they wither and die. The roots of the drought-resistant rosemary rot from too much moisture retention caused by clay, compacted soil, or soil without sand amendment, which causes the leaves to turn brown and die.
Rosemary has a unique adaptation for growing in sand or grit, which encourages very quick drainage and does not retain moisture. As a result, it cannot tolerate soil that is consistently damp.
For optimal drainage and root respiration, rosemary needs soil that has a high inorganic content and a porous structure.
To assist imitate the ideal soil conditions of the rosemary’s natural Mediterranean climate, horticultural sand, grit, or perlite should be added to even regular multipurpose compost.
With too much moisture surrounding the roots, slow-draining soil causes the rosemary to become stressed, which manifests as drooping branches, brown (or yellow) foliage, and a generally sickly appearance.
If your rosemary plant is exhibiting signs of root rot, reduce the amount of watering you give it because doing so will only make matters worse.
The best technique to salvage a rosemary plant that is withering in wet soil is to replace it in a new pot because pots have much better drainage than raised beds or garden borders. To ensure that the rosemary has adequate room for its roots to spread out, use a pot that is around 12 inches across and proportionately deep.
(Read my post on selecting the ideal pots for rosemary.)
The additional benefit of using pots over amending garden soil is the ability to properly tailor the soil conditions to suit rosemary by simulating their original soil in pots.
Sand encourages adequate drainage to reduce the chance of root rot, thus it is always preferable to add more sand or grit to the potting mix than less.
At least 30% of the potting mix should be sand or gravel, and 70% of it should be compost. It may take as much as 50% more sand in high-rainfall regions to provide the proper degree of drainage to offset the rising dampness.
Always look for evidence of root rot (mushy texture, rotten, dark brown appearance, and foul odor) while repotting, and use pruners to cut off the infected roots as with overwatered rosemary.
If there is severe root rot, it may be impossible to rescue the plant; nevertheless, if there are any healthy branches still present, you can try to propagate the rosemary by taking a stem cutting.
To avoid the issue in the future, it is frequently preferable to purchase a new plant and pot it up with a lot of sand to replicate the Mediterranean soil conditions that the rosemary prefers.
(Check out my piece on the best potting soil for rosemary.)
3. Not Enough Sunlight
Rosemary lives in open, exposed regions where they receive full light all day in their native Mediterranean hilly range in North West Spain and Portugal.
I must emphasize that while rosemary may be grown wherever in your garden that receives the most sunlight—they are hardy to USDA zone 6—and you do not need a Mediterranean environment to do it.
The quantity of essential oils in your rosemary’s leaves, which are what give it its particular flavor and perfume, is associated with how much sun it gets.
For rosemary to remain healthy, it needs full daylight, which entails six hours of direct sunlight each day during the spring and summer. Less sunshine causes the rosemary’s leaves to lose their perfume, turn brown, produce fewer blossoms, and eventually wither away.
In order to lessen the risk of fungal diseases like root rot, more sunlight also enhances evaporation from the surrounding soil and lowers humidity.
It is crucial to relocate your rosemary to a garden area that receives more sunlight if it is experiencing poor growth, an unpleasant aroma, browning leaves, or a lack of summer blooms (see my post on why my rosemary isn’t flowering?).
Even if you have to move the rosemary to the front of your house to find the additional hours of sunlight, with at least 6 hours of sun per day, having a potted rosemary makes moving it to the new, sunnier place much easier.
It is urgent to move the rosemary if it was planted in a raised bed or garden border, either to a location with more sunlight or to a container.
Rosmerry can be transplanted at any time of year because it is resilient, but spring and fall are the best times because they save the plants from the summer sun and high temperatures while they are establishing themselves.
Although it is feasible to transplant rosemary in the winter, it is better to avoid doing so since this may make the plant more susceptible to root rot. If, however, the rosemary is too much in the shade and starting to die back, I advise transplanting at any time of the year.
In order to increase drainage and to mimic the soil conditions of the rosemary’s native home, replant the rosemary in a sunny location 2-3 feet away from other plants.
4. Soil is Too Acidic (Rosemary Prefers Soil pH 6-7.5)
While it can survive some acidity, rosemary has specifically adapted to growing on the calcareous soils on the hill sides of Western Mediterranean Europe. It does not fare well on rich acidic soils.
As certain nutrients become insoluble due to soil acidity, which makes it harder for the rosemary’s roots to absorb the nutrients they need, the rosemary may not live as long or achieve its potential in terms of growth, fragrance, and culinary taste of the leaves if your garden soil is more acidic than pH 6.
As the pH level that organic plant material normally reaches after it is fully decomposed, the majority of garden soils are neutral or slightly acidic, making them excellent for producing rosemary and other Mediterranean herbs.
However, some garden soils have a high natural acidity, which may be the cause of your rosemary’s decline.
If you are unclear of the pH level of your garden soil, I advise buying a cheap soil test kit from Amazon. They are really simple to use and are quite reasonably priced!
To keep your rosemary from dying, you will need to transfer it if you discover that the soil is too acidic.
It is crucial to transplant your rosemary to a pot with new potting soil if your soil is too acidic from growing rosemary (use 70% potting soil or multi-purpose compost to 30% sand or grit for drainage).
Use a garden fork to gently lever the rosemary plant out of the ground rather than yanking it out with force. This will prevent cutting through the roots.
To guarantee that the roots have enough room to spread out and to protect the temperature-sensitive roots from cold weather, replant your rosemary in a pot that is at least 12 inches across and proportionately deep.
Due to the ideal drainage conditions and the fact that you may alter the oil mix to more closely resemble their natural environment by using a lot of sand or grit, rosemary grows incredibly well in pots.
If it is Spring or Summer, the rosemary should begin to show symptoms of recovery within the following few weeks. If it is Fall or Winter, the rosemary plant may be dormant within the next few months.
Although it is possible to apply soil amendments to make your garden soil less acidic, it is always simpler and less expensive to replant the rosemary in pots.
5. Wrong Climate for Rosemary
Rosemary is native to the Mediterranean region of Europe, where it thrives in full sun, moderate spring and summer temperatures, mild winter temperatures, and minimal precipitation.
Rosemary is typically regarded as a half-hardy plant that can withstand a little bit of light frost, but it truly benefits from protection from the worst of the Winter weather because rosemary frequently dies from severe frost.
As they are hardy to USDA zone 7, varieties including “Arp,” “Hill Hardy,” and “Salem” are a little better at weathering lower temperatures.
The rosemary, on the other hand, can frequently die back in a cold Winter with a strong frost because of both frost damage and cold, damp soil, which encourages the conditions for root rot and is utterly at odds with the rosemary’s preferred warmer and dryer Mediterranean conditions.
The rosemary plant’s most vulnerable to cold temperatures are its roots.
The dirt in their natural environment can effectively shield the roots from cold weather.
However, smaller pots also hold less soil, which offers the rosemary’s cold-sensitive roots less insulation and raises the possibility of frost damage.
However, there are some ways to prevent this.
The answer is…
The best course of action if you live in an area where winter frosts are common is to grow your rosemary in pots and either bring them inside for the winter (and place them in a sunny window or greenhouse) or use horticultural fleece to wrap around the plant and the pot to protect it from damage from lighter frosts.
Always use a pot that is at least 12 inches across when planting rosemary because a bigger pot can hold more soil, which works as insulation for the roots’ sensitivity to cold temperatures.
Growing rosemary from cuttings in the summer is another smart move.
This is quite simple, and the cuttings that are propagated frequently have a high success rate. Hormone rooting powder is added, and the cuttings are then placed in a sunny window for the winter.
If your main rosemary plant perishes in the frost, this can offer a nice supply of free young rosemary plants as a backup plan.
6. Conditions Too Humid for Rosemary
Rosemary is indigenous to the Mediterranean, where temperatures are high yet frequently dry.
It is not recommended for rosemary to grow in humid regions with slow soil evaporation rates because too much moisture in the soil or surrounding the plants can encourage the growth of pathogens that cause root rot.
Rosemary plants that are overwatered or in soil that drains slowly exhibit brown or yellow, drooping leaf and a dead appearance as indicators of stress, as do rosemary plants that dwell in excessively humid environments.
Rosemary enjoys open spaces with good air circulation and can tolerate some sea wash because it is most frequently seen along the ocean on hill sides. Rosemary can tolerate some humidity if the growing environment is modified.
Any Mediterranean herb, including rosemary, must be placed in an open space, about 3 feet apart from other plants, in order to tolerate humidity.
The better for the rosemary is an area with good ventilation that is more exposed.
Planting rosemary in pots in humid places is a terrific strategy to position the plant properly in the windiest part of your garden. By lifting the plants out of the soil in pots, you are also reducing the amount of moisture around the plant.
It should be underlined that in humid locations, rosemary needs well-draining soil and sparing watering even more. For rosemary in humid locations, I would advise using up to 50% sand or grit to 50% potting soil to lower the danger of root rot.
Use a white stone mulch (available from garden centers) to surround your plant, even if it is just in the pot, as this can help reflect more light back onto your rosemary and increase photosynthesis as well as possibly increase the concentration of essential oils in your rosemary leaves for a better aroma and taste. This is a great tip I learned from commercial lavender growers (which require very similar conditions to rosemary).
In order to promote temperature and moisture evaporation, reduce humidity surrounding the rosemary, and produce a dryer microclimate that mimics the drier conditions of the Mediterranean region, a white stone mulch also aids in light reflection.
In humid climates, rosemary can thrive with a few minor changes to the growing environment.
7. Heavy Pruning Can Kill Rosemary
The most crucial piece of advice for pruning rosemary is to only remove woody, older growth, never softer, more flexible branches. Aggressive pruning stops new rosemary stems from sprouting, which causes it to die back. The old woody growth does not regenerate or grow new stems after being trimmed back.
The answer is…
It’s crucial to prune your rosemary each year to keep it in shape and to promote the best-tasting new growth for cooking.
To give the plant time to heal from any wounds before Winter, only cut the rosemary back by about 1/3 in the spring or fall, ideally a month before the first frost.
Because rosemary only blooms on new growth, it is preferable to prune it in the fall if you want to promote flowering and live in a region with a warm winter. Late spring trimming can actually prevent or postpone flowering.
As pruning in the fall can help to stimulate new fragile growth, which is considerably more susceptible to low temperatures, pruning rosemary in the spring is preferable in colder locations with frost over the winter.
By keeping its shape and preventing the old wood from shattering in winter storms, pruning rosemary also reduces its susceptibility to winter damage.
The simplest method to explain how to trim rosemary is always with a visual aid, so watch this YouTube video for an easy explanation:
8. Too much Fertilizer Causes Rosemary to Turn Yellow
If the leaves on your rosemary plant are yellowing or drooping, this may be a sign of too much nitrogen in the soil as a result of either direct fertilizer application or fertilizer runoff from your lawn.
Rosemary grows best when neglected rather than given careful attention; in fact, it develops leaves with a stronger scent and more distinct flavor in medium- to low-fertility soil.
In its original Mediterranean habitat, where the soil is somewhat poor, sand- and grit-filled, rosemary thrives best and yields the tastiest leaves for cooking.
While too much nitrogen in the soil encourages the growth of foliage, it also suppresses blooming and diminishes the amount of essential oils, which are what give rosemary its distinctive flavor and perfume.
Additionally, too much nitrogen results in weak, drooping growth, which leaves the plant more susceptible to aphid infestations and diseases that can cause the rosemary to die back.
As opposed to the sandy soil conditions to which they are suited, mature rosemary plants do not need any additional fertilizer.
It’s possible that the soil has too many minerals for lavender if the rosemary is yellow and drooping and you haven’t added any fertilizer.
Stop applying any fertilizer and, preferably, repot your rosemary in new potting soil that has a sand or grit content of at least 30% to 70% potting soil or multipurpose compost.
It is important to note that rosemary has evolved to grow in rocky, sandy soils with low to medium fertility, therefore by adding sand to the potting mix, you are simulating the original soil of the plant.
Sand does not significantly add nutrients to the soil, which will balance out the soil’s naturally high nitrogen content and enhance drainage.
The rosemary should recover quite well in the coming weeks if you prune back any extra, drooping growth in the spring and summer.