Azalea plants are cultivated all over the world so watering requirements very much depends on your specific climate and soil conditions. Therefore it is difficult to prescribe an exact amount of water for your azaleas to stay healthy.
Azaleas are shallow rooted plants so the goal is always to keep the soil moist at the but not saturated which is partly achieved with good soil preparation and applications of organic mulch.
Watering with generous amounts encourages the roots to establish and can increase the azaleas resistance to drought.
This table gives you a broad overview of how to water azaleas according to the different conditions.
|Azaleas Conditions||How to Water|
|Outdoors in optimal conditions||Azaleas that are in prepared soil, with mulch and in partial sun light will only need watering if there hasn’t been significant amounts of rainfall in the last 14 days. Water generously with around 4 litres or a gallon to ensure the soil is moist (but not saturated).|
|In pots and containers||Pots tend to dry out much quicker so water diligently once per week with around 4 litres or a gallon of water per week, but most important is to ensure that the soil is moist.|
|Indoors||Consistent watering is essential to maintain the correct moisture balance of the soil. Water once or twice per week (depending on how dry your climate is) and keep the soil moist but not saturated. Check the soil moisture regularly and water accordingly whenever it feels like it’s drying out.|
|Azaleas in the sun/dry climates/times of drought||Azaleas in full sun or dry climates need regular watering in conjunction with mulch to retain water. At the hottest and driest times water 2 or 3 times per week. Look out for signs of drought (leaf curls and brown colour).|
|Azaleas in full shade||In full shade, with well prepared compost and mulch azaleas will only need watering in times of drought.|
|Sandy soils||Sandy soils drain too quickly for azaleas. Amend the soil with organic matter and water as often as required to keep the soil moist.|
|Slow draining soils||Slow draining soils will promote the conditions that cause root rot. Amend the soil with organic matter and gravel for improved drainage.|
|In Winter||Azaleas generally don’t need watering in Winter unless they are indoors. In which case water occasionally so the soil does not dry out completely and resume watering in the Spring.|
Keep reading for more details and best practices of watering azaleas according to your conditions and why its important to water with rainwater rather then tap water…
Watering Outdoor Azaleas
How much water and how freequently you should water azaleas depends on:
- How well the soil is prepared before hand
- The use of a water retaining organic mulch such as leaf mould
- How quick the soil drains
- The climate and whether conditions
- How much sun/shade the azalea has per day
Azaleas plants require a balance of consistent moisture in the soil so the plant stays hydrated but the soil cannot be saturated as this encourages the fungal disease root rot (Phytophthora) .
Watering azaleas successfully is all about creating soil that is moist in the growing season and adjusting the conditions to promote moisture retention in conjunction (such as added mulch) with additional watering to maintain the correct balance.
It is important to prepare the soil beforehand with water retaining materials such as leaf mould. (Read my article on how to prepare soil for azaleas).
Leaf mould has the capacity to absorb water so that the roots can draw upon the moisture as they need to, but it still retains a structure that allows the excess water to drain away so that the roots do not become saturated.
Additionally mulch (composed of leaf mould or compost) will help to conserve water and keep the roots cool in summer.
Prepared soil before planting and regular mulch will cut down the amount you need to water azaleas dramatically to the point that you may only need to water in times of drought.
In quick or slow draining soils you need to customize the watering schedule according to the moisture of the soil.
Fast draining soils naturally need a lot more water. Water azaleas twice per week in the growing season if the soil is sandy. Make sure to add a mulch to help improve the soils capacity to maintain a balance of moisture and improve the soils structure.
Slow draining soils are will need less watering and will be at greater risk of root rot. If the soil is consistently boggy or saturated rather then just moist then it is imperative that you remove the azalea and plant it in an area of better drainage or perhaps a pot or raised bed to lift it out of the saturated soil.
In dryer climates or azaleas planted in full sun you need to be more diligent with your watering schedule. I would recommend that you water at least twice per week with at least 4 litres or a gallon of water and frequently check the surrounding soil for moisture.
Watering generously helps to encourage the roots to establish, azaleas are shallow rooted by nature, but if the plant does not receive enough water he roots grow close to the surface to find rainwater which makes the azalea more susceptible to drought.
Potential Problems- Tree Roots Stealing Moisture
Many varieties of Azaleas appreciate some shade rather then full sun. This is one of the reasons for the popularity of azaleas and rhododendrons as they grow well and produce spectacular flowers under trees or in shady areas of your garden.
However tree roots, particularly those with shallow roots such as pines beech, spruce etc. can be problematic as trees are efficient at drawing up moisture. This puts it in direct competition with your azalea which also has a shallow root system.
The solution is to give your azalea a competitive advantage by watering once or twice per week (or as frequently as you need to, for the soil to be moist) and apply a layer of mulch to lower evaporation and improve the soil structure so that water infiltrates to the roots of the azalea.
Watering a Newly Planted Azalea
Newly planted azaleas require more frequent watering as their roots require time to adjust and establish to the soil.
For this reason, Fall planting is often recommended as evaporation tends to be lower at this time of year and the soil is still warm from Summer, although azaleas can be planted at anytime of the year apart from Winter.
Water newly planted or transplanted azaleas at least twice per week with around 4 litres or a gallon of water. It is very important that the soil remains moist and well watered for around a month as the plant adjusts to its new soil.
Do not over water by soaking the plant every day as this will cause the azalea to develop root rot.
Always apply mulch composed of rich organic material after planting as this will maintain the optimal moisture balance that a newly planted azalea requires as it tries to establish.
Watering Azaleas in pots
Azaleas can grow very well in pots, however they are higher maintenance in terms of the frequency of watering.
Pots are naturally more well draining then most garden boarders, therefore the need for additional watering increases.
In most conditions, if the has been well prepared and is composed of organic matter then azaleas in pots or containers, in partial shade only need watering once or twice per week.
However in times of high temperatures and little significant rainfall the frequency of watering should increase to perhaps once every other day.
If you have used the correct potting mix for azaleas then this will help you to maintain the moisture of the soil in times of drought and high temperatures. For the full guide, read my article on the optimal soil mix for azaleas in pots.
Watering Azaleas Indoors
For indoors azaleas the frequency of watering will depend on a few factors such as:
- Whether your climate is humid, temperate or arid
- The size of the pot (due to the amount of soil it can contain)
- The potting soil (whether it retains moisture or drains too quickly)
Whether an azalea is indoors or outdoors the goal with watering should be to keep the soil moist without out it becoming boggy.
So in arid climates it is likely that you will need to water the azalea two or three times per week. Whereas in humid climates the azalea may need to be watered only once per week.
Indoors you should also take into account air conditioning draughts and heating that may influence how often you need to water the azalea.
Air con can be very drying as of course can heat at certain times of the year so try to avoid your plant directly in the firing line of draughty areas but if this is unavoidable, check the soil moisture regularly and water proactively before the soil dries out.
The smaller the pot for your azalea the less soil it will contain which means there is a limited amount of water available in the soil. Not to mention small pots naturally dry out quicker in warmer weather so aim for a a larger pot but remember you can always upgrade to a bigger pot as the azalea grows.
The most important factor is the potting soil. Leaf mould and compost are a great combination as the naturally hold onto moisture which is particularly useful for homes in arid climates. To learn more, I have an article on the optimal potting mix for azaleas.
Avoid this mistake!
A very common mistake with house plants of all kinds is to water the plant with a drip tray underneath or the pot (which should have drainage hole in the base) may be placed into a bigger decorative pot which does not allow for drainage.
This inevitably leads to the soil becoming boggy and promotes the conditions that allow for root rot which can kill the plant.
Always let the water drain out the bottom of the pot. The best way to do this is to move the plant to perhaps the garden or the sink for half an hour so that the excess water has drained away.
How to tell if your Azalea needs Watering
Azaleas have a naturally shallow and fibrous root network so when there is a drought or dry weather they are often show signs of stress before other plants.
The most obvious sign of stress is a wilting appearance and the leaf curling slightly.
In these conditions it is essential that you water the azalea as quickly as possible to help revive the plant. If the wilting appearance is addressed quickly then there should be no lasting damage to the plant.
However if the plant experiences drought in the Spring then it may stunt the new growth of the azalea to some extent over the Summer and could affect flowering.
It is a good idea to test the soil regular to proactively avoid the azalea experiencing drought. The best way to do this is to simply place your finger into the soil surrounding the azalea. If its moist but not saturated then this is the optimal balance that azaleas require.
However if you detect the soil beginning to feel dry to a finger depth then this will indicate that the azalea needs watering with 4 litres or a gallon of water.
The soil should always have a soft aerated structure so that you can easily test it with your finger rather then a baked hard soil. To achieve this soil structure you need to prepare the soil properly beforehand and crucially, continue to add organic mulch to the soil at least once per year in the Spring.
Adding Mulch to Conserve Water
Adding mulch around your azalea is a crucial to ensure that you plant has access to enough moisture.
The best time to apply mulch is in the Spring as this will help to add nutrients to the soil and retain moisture before the hottest time of the year.
Apply a one inch layer of organic material around the root ball of the azalea, on the surface of the soil but leave a gap of a few inches between the mulch and the wood of the azalea as the wood above ground does not like to be in contact with moisture.
In climates that experience significant rainfall, a layer of mulch may conserve all the moisture your azalea needs with little or no additional watering.
The best materials for mulch is organic matter such as:
- Leaf mould
- Well rotted manure
All three of these materials has the capacity to hold moisture yet retain a structure that allows excess water to drain away. Not only that but they will soften the texture of the ground which will allow rain and water to infiltrate the soil more effectively, rather then running off the surface.
Leaf mould composed of oak and beech leaves are particularly good as they hold significant moisture and they are acidic so it will help to preserve the azaleas preferred acidic soil pH of 4-6.
In addition to conserving moisture and improving soil structure, mulch will benefit your azalea in a lot of different ways such as:
- Slows down soil evaporation
- Suppress weed growth
- Add nutrients to the soil
- Improves infiltration of water
- Stimulates the soil ecology
Water with Rain Water, Not tap Water
Azaleas prefers acidic soil for growing with a pH of between 4-6 (7 is neutral and more then 7 is alkaline). Azaleas will not grow in alkaline as they can not access certain nutrients if the soil is not acidic.
Tap water is often pH neutral and can even be alkaline in certain areas. Watering azaleas, rhododendrons, camellias with tap water can over time alter the pH of the soil so that it is closer to neutral rather then acidic.
This can lead to problems such as yellow leaves which may indicate as an iron deficiency and stunt the plants growth. (Read my article on the solution for azaleas with yellow leaves).
The solution is to water you azaleas with rain water as this tends to be more acidic with a pH of 5.6 which puts it in the ideal range of the azaleas preferred soil pH.
Rain water will help to keep your azalea healthy and ensure that the roots can access all the nutrients they need.
The best way to collect rain water is from a water butt that is connected to the guttering of your garage or house roof. This the easiest and most effective way to collect rain water and will ensure that you always have enough for watering your plants.
- How much and how often your azaleas require watering depends on several conditions. The aim should always be to kept the soil moist but not saturated, and you should adjust your watering frequency to meet this balance.
- Preparing the soil before planting azaleas with organic matter that retains moisture yet lets excess water drain away from the roots is essential to keep the plant healthy.
- Outdoor azaleas in properly prepared soil, in some shade with a Spring application of mulch may only need watering in times of drought whereas azaleas in fast draining soil with lots of sun will need watering every couple of days in summer.
- Azaleas in pots whether it is indoors or outdoors tend to require more attention as pots tend to drain quicker then garden soil. Watering twice per week in the Summer will keep the plant healthy.
- Azaleas that have just been planted or transplanted require significant watering for the first month and a application of mulch to retain water. An azaleas is most vulnerable to the affects of drought immediately after planting so water the azalea every other day for the first month until the root becomes established.
- Add mulch around the azalea at the start of spring to help preserve moisture and improve the soil structure.
- Always water with rain water if possible as rain water tends to be slightly acidic whereas tap water can be neutral or even alkaline. Azaleas need an acidic soil pH to be able to access nutrients.