Hydrangea


Hydrangea macrophylla



Contents

  1. Top Tips
  2. Location, Water, Humidity & Fertilisation
  3. Dormancy Care & Annual Blooms
  4. Common Issues
  5. Origins, Temperature, Propagation, Repotting & Toxicity.


Book a 1-to-1 video call with Joe Bagley if you'd like a personal guide to repotting your houseplant. This will include recommending the right branded-compost and pot size, followed by a live video call whilst you transplant the specimen for step-by-step guidance and answer any further questions!




Top Tips & Info

  • Care Difficulty - Moderate to Hard
  • Hydrangea like bright, indirect light away from excessively dark situations. Although an hour of direct sunlight in the early morning is perfect for growth, be sure not to fall in the trap of sun-scorch and dehydration in the excess sun.
  • Provide near-constant moist soil, allowing the soil's top third to dry out in between waters. Reduce irrigation slightly further in the height of winter. 
  • Supplement every two weeks in the spring and summer, using a 'Houseplant' labelled fertiliser to ensure quality foliage and flower development. Reduce this to monthly intervals for the autumn and winter period. 
  • Repot every two years during the spring, using a 'Houseplant' labelled potting mix and the next sized pot.
  • Keep an eye out for Spider Mites & Aphids that'll hide in the plant's cubbyholes and underneath the leaves.
  • Indoor-purchased specimens can be placed outdoors after the risk of frost has elapsed in the spring onwards. They will acclimate to the new environment, and may even survive the following frosts and winters to become a permanent feature in the garden! Do not bring outdoor specimens back in the home due to the risk of pest introduction and environmental shock.




Location & Light - 🔸🔸

If you're a forgetful waterer, avoid direct sunlight costs - the combination of too little soil moisture and intense rays will quickly lead to a miserable plant. If, however, you can provide good soil moisture throughout the year, a splash of either morning or evening sun will significantly benefit the Hydrangea. Never situate this plant in a shady spot; if you're worried about its location being too dark, if a newspaper can be read while having your back towards the light source, you're good to go.

Location: Place this on, or within two metres of a north-facing window if you tend to under-water plants. A metre away from an east or west-facing windowsill is the ideal location for good quality growth over the year. Never situate an indoor Hydrangea in full sun, or a setting that'll exceed the maximum temperature bracket of 25ºC (77ºF) - an example of this would be a south or west-facing conservatory.


Water - 🔸🔸🔸

Hydrangeas love good soil moisture; hence the prefix, hydro. Once the top third of the soil has dried out, rehydrate by using the bottom-up method to reduce the chance of fungal diseases associated with excess moisture on the foliage. Submerge the bottom fifth of the pot in a saucer of water until thorough absorption. Repeat this step weekly, especially with those grown in bright, warmer locations. Whilst the plant is in bloom, it's essential not to use cold water as this will quickly shock the roots, causing multiple issues down the line. Under-watering symptoms include rapid flower loss and dry, sunken leaves; these issues are usually due to either forgetfulness, too much sunlight or too much heat. Over-watering symptoms include rotting lower leaves, yellowing leaves, a loss of buds or flowers, and root rot. Allow the majority of the soil to dry out in between waters, preventing a pool of standing water from accumulating beneath the pot.


Humidity - 🔸🔸

Create a humidity tray to provide a moist and stable environment for your plant. If the surrounding saturation is too low or the heat too high, its leaf-tips may start to brown over and curl, especially in direct sunlight. Gently hose the foliage down from time to time to hydrate the leaves and keep the dust levels down.


Fertilisation - 🔸🔸

Feed fortnightly during the spring and summer, using either a 'Houseplant' or potassium-based feed during the flowering period; 'Tomato' fertilisers are an excellent choice for this time. A general plant fertiliser is acceptable too, but remember to dilute the solution by half to prevent the burning of roots.




Dormancy Care & Annual Flowers

Provide a bright, and cool autumn and winter period around 15℃ (59℉) to reinforce its dormancy. Keep the roots pot-bound to add further stress onto the specimen, which in turn will significantly heighten the chance of flowering. Blooms will generally appear in the summer, during the active growth season. 

The following steps should be taken from early autumn until the end of winter. 


Sunlight & Location

Be sure to provide a bright location with little to no direct sunlight. Although the winter rays won't necessarily hurt the plant, be careful not to fall in the trap of sun-scorch and severe dehydration. Avoid deep shade and the use of artificial lighting at night or locations that boast temperatures higher than 18℃ (64℉).


Hydration

Reduce waters so that at least half of the soil becomes dry. It's essential to keep them on the drier side to life, as they'll think that hard times are ahead and therefore will need to pass its genes on to the next generation.


Occasional Feeds

During the autumn and winter, fertilisation should be performed at monthly intervals with a 'houseplant' feed. While the flowers are in development or in bloom, use a Tomato fertiliser to provide fortnightly nourishment of potassium.


Reduce Everything

This is to remind you that everything needs to be reduced - especially the temperature.


Temperature

This is the most significant step; reduce the temperature down by around 5℃ compared to the summertime or place in a room that's between 14º - 17℃ (57º - 62℉). You'll be at a significant disadvantage if the ambient temperature is kept constant throughout the year, as Hydrangea will respond best in locations that have daily fluctuations of around 7℃. Never exceed the minimum temperature as it may lead to plant death or yellowed foliage at a bare minimum. After the last flower elapses, be sure to prune the foliage slightly to  If these steps are followed successfully, you could see a show of blooms in the following summer - but remember, dealing with nature may not always provide the results you'd relish.




Common Issues with Hydrangea

Dry soil is a big issue when cultivating Hydrangea. Although they can withstand slight droughts over time, persistent dry spells will considerably weaken the plant, potentially causing death. Stunted growth and flower loss are the typical signs of under-watering; if it doesn't bounce back after severe wilting, it may spell the end of its life. Be sure to avoid direct sunlight and potentially create a schedule if you're a forgetful gardener.

Too much sunlight will lead to sun scorch, with typical signs including browning or crispy leaves, dry leaf-edges, sunken leaves or stunted growth. Although too little light will cause over-watering issues, too much sunlight will negatively affect the plant as well. A location that offers over two hours of sunlight a day will bring the optimum growth for the Hydrangea. If yours has fallen short of this issue, reduce the amount of direct light considerably and always be mindful of environmental shock (when too locations offer too different growing conditions). Remove some of the affected leaves and increase waters slightly. Only hydrate the plant using the bottom-up method.

Mealybugs are also a common issue - small, white-coloured critters are most likely to infest the cubbyholes of the flowers, foliage or even the stem. Each female mealybug can lay up to six-hundred eggs in her lifetime, meaning that an infestation can be imminent. The best way to prevent an attack before it becomes a threat is by keeping the windows and doors shut, with regular pest inspections. For those that have unfortunately bitten the dust, click on this link to learn about addressing these issues.

Spider Mites are small, near-transparent critters, that'll slowly extract the chlorophyll from of its leaves. Have a check under the leaves, most notably along the midrib, for small webs and gritty yellow bumps. Click here to read our article about the eradicating Spider Mites, along with some extra tips that you may not find elsewhere!

A sudden loss of older flowers with a wilting stalk is a sign of prolonged droughts. Especially during the flowering process, near-continuous moist soil is mandatory for extended blooms.

A lack of flowers is caused by an insufficient dormancy period, where the temperatures are kept more or less the same over the year. Reduce the temperature by a couple of degrees over the autumn and winter months, along with fewer irrigations to ensure a well-spent dormancy. As spring arrives, the natural temperature will begin to increase, with this is being the perfect time to increase waters and fertilisation. Remember, the warmer the summer days are, the more likely a specimen is to reflower.




Origins

Hydrangea is a genus consisting around seventy species, with distributions across North America and Eastern Asia. The genus was first described back in the 1750s by Carl Linnaeus during a visit to the Americas. Hydrangea comes from the Latin words for 'water capsulesthat refer to the shape of the seeds put out in spring or summer. The specific epithet of the most popular species, H. macrophylla, can be translated from ancient Greek to mean 'large-leaved'.


Temperature

5° - 25°C   (40° - 78°F)
H2 (Hardiness Zone 10) - Tolerant of temperatures above freezing. This plant will die if left in temperatures below frosts; move to a conservatory or greenhouse until this risk has elapsed.


Spread

When grown indoors, they can grow up to 1m in height and 0.8m in width. The ultimate height will take between 4 - 6 years to achieve.


Pruning & Maintenance

Remove yellow or dying leaves, and plant debris to encourage better-growing conditions. While pruning, always use clean utensils or shears to reduce the chance of bacterial and fungal diseases. Never cut through yellowed tissue as this may cause further damage in the likes of diseases or bacterial infections. Remember to make clean incisions as too-damaged wounds may shock the plant, causing weakened growth and a decline in health.

From late winter to early spring, prune leggy growth to promote a bushier appearance and remove spent flowers or plant debris.


Propagation

Via Seed or Stem Cuttings.

Stem & Eye Cuttings (Moderate) - This method of propagation is troublesome without the aid of bottom-heat and a controlled environment. Choose the healthiest, most established stems that are wooded, yet still juvenile enough to bend slightly, being just thicker than a phone charger wire. Each cutting should only have a few leaves leaf, above 8cm of semi-wooded stem. Situate the cutting's lower half into moist 'Houseplant' compost; 'Blackleg' can occur when the bottom wound becomes infected, resulting in propagation failure - typically caused by water-logging or deep damage. Maintain bright light and evenly moist soil with the avoidance of direct sunlight or cold draughts. Wrap the pot (& foliage) in a transparent bag or within a miniature greenhouse, and provide bottom heat of temperatures above 18°C (54°F). Remove the bag and place into individual 7cm pots once the second new leaf emerges. Follow the same care routines, as mentioned in the article's top half. This method will take up to five months, so patience and the correct environment are paramount for success!


Flowers

Most indoor Hydrangea will flower between the months of spring or summer, lasting several weeks or even months. The blooms are arranged in globular panicles, laying just above the foliage line to attract airborne pollinators. Hydrangea usually sport either white, red, purple, blue or pink coloured flowers, with cultivars and hybrids being a mixture.


Repotting

Repot every three years in spring using a 'Houseplant' labelled potting mix and the next sized pot with adequate drainage. Hydrangea are far better potbound for several years due to the heightened risk of root rot and repotting-issues (like transplant shock), so only repot if you feel it's wholly necessary - restricted root growth will also increase the chance of blooms, too.

Hydrate the plant 24hrs before the tinkering with the roots to prevent the risk of transplant shock. For those situated in a darker location, introduce an extra amount of perlite and grit into the deeper portion of the pot to downplay over-watering risks. Click on this link for a detailed step-by-step guide on transplantation, or via this link to learn about repotting with root rot.

Book a 1-to-1 video call with Joe Bagley if you'd like a personal guide to repotting your houseplant. This will include recommending the right branded-compost and pot size, followed by a live video call whilst you transplant the specimen for step-by-step guidance and answer any further questions!


Pests & Diseases

Keep an eye out for mealybugs, aphids, spider mites, scale, fungus gnats, whitefly, blackfly, vine weevils & root mealybugs that'll locate themselves in the cubbyholes and undersides of the leaves, with the exception of the latter two in soil. Common diseases associated with Hydrangea are root rot, leaf-spot disease, botrytis, rust, powdery mildew & southern blight - click here to learn more about these issues.


Toxicity

Not known to be poisonous when consumed by pets and humans. If large quantities are eaten, it may result in vomiting, nausea and a loss of appetite.


Retail Locations

Some florists & Online Stores. Specimens are likely to be found in summer outside at most garden centres; it's not advised to bring outdoor plants inside as this could lead to environmental shock and introducing foreign pests into the home.



Book a 1-to-1 Call with Joe Bagley

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