Opuntia Humifusa Care – Best Tips!

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Opuntia humifusa, also known as ‘prickly pear’ is a hardy cactus indigenous to the North-Eastern corner of the USA and Southern Canada.

It is an exceedingly hardy plant and grows naturally in sandy soils, rocky outcrops, and on cliffs.

Opuntia humifusa tolerates extreme winter conditions including sub-zero temperatures, snow, frost, and heavy rain.

Exposed to harsh winter conditions, it will shrivel slightly and you will see the skin turn purple and crinkly.

But come spring, it will be revitalized and start to sprout new cladodes which grow sideways until they reach the ground where they re-root and form clumps of cacti.

It will generally reach a maximum height of around 2ft (60cm ) and a maximum spread of 5ft (1.5m).

Opuntia humifusa features roundish-oval, flattened pads which are fleshy and green with a purple tinge. The pads are covered in minuscule reddish-brown spines.

The spines or ‘glochids’ can be extremely sharp and should only be handled if wearing gloves.

In early summer, Opuntia humifusa produces yellow flowers. These are then followed by the prickly pears themselves. The fruits are initially green but then change, first to yellow and then purple. 

 

 

Opuntia Humifusa Care

Opuntia humifusa is easy to grow and requires very little maintenance. It is an incredibly hardy plant that tolerates almost all weather. For best results, all it requires is a sunny location with 6-8 direct sunlight and, free-draining soil, and good airflow. Water once a month indoors. The best temperature range for this cactus is between 65-90°F (18-32°C). You don’t need to fertilize your plants if they are grown in the garden, but an application once or twice a year can be beneficial.

 

Where to grow your Opuntia humifusa

Opuntia humifusa can be grown in the garden or in pots indoors. It should be positioned in full sun and ideally get 6-8 hours of direct sunlight each day.

 

Watering

Opuntia humifusa is a drought-tolerant plant that requires only a small amount of water. It prefers dry soil and although it will cope with long spells of wet weather, it will not thrive in them.

If planted outside you will usually only need to water the plants during the summer months.

They may require the occasional watering during spring but you should allow the soil to dry fully before watering and if you are unsure, it’s better to err on the side of caution. 

Grown indoors, water sparingly, and allow the soil to fully dry before watering. You should not need to water more than once a month.

 

Temperature

The ideal temperature for Opuntia humifusa when kept indoors is between 65-90°F (18-32°C). It can tolerate cooler temperatures throughout autumn and winter down to around 45-55°F (7-13°C) while they’re dormant but don’t like fluctuations in temperature.

If you are growing your Opuntia humifusa outside in the garden, it should receive around 6-8 hours of sunlight during summer days.

They grow in USDA hardiness zone 3b to 11.

 

Humidity

Opuntia humifusa is one of the hardiest cacti available. Its optimum humidity will range between 40-60% but it will tolerate extremes. 40-60% is normal for most households during the summer months.

 

Fertilizing

Opuntia humifusa does not need fertilizer when it is planted outdoors but that doesn’t mean a dose once or twice a year won’t benefit it.

Any all-purpose fertilizer (diluted to half) will do and an application once in spring and again in summer will provide all the nutrients your plants need. Too much fertilizer can be damaging to plants to be sure not to apply any more than that.

When kept indoors, your Opuntia humifusa will not receive any nutrients naturally so you will need to fertilize it. A houseplant fertilizer is sufficient. As when fertilizing other houseplants use it at half-strength. An NPK formula of 5-10-5 works well.

Cacti do not have outlandish requirements when it comes to fertilizer. Houseplant fertilizer diluted at half strength will do. Phosphorus and Nitrogen are specifically important for cacti.

A 5-10-5 solution can work well. Again, apply sparingly and err on the side of caution. If you see your plants turning from bright green to pale green, this could be an indication that fertilizer is required.

 

Air circulation

Good air circulation is crucial for your Opuntia humifusa to thrive. At night, cacti absorb carbon dioxide via stomata in their stems which they use for photosynthesis during the day. 

When planted outside, your Opuntia humifusa plants will naturally receive good airflow as long as you choose a suitable position that receives direct sunlight. 

If you are growing them indoors, placing them near an open window or using a fan to gently circulate the air may be necessary but by not crowding them with other plants you should avoid the need to provide additional airflow.

 

Propagation

Opuntia humifusa can be propagated from seeds or pads. Seeds can be bought from a garden center or harvested from the fruits at the end of the growing season.

To obtain the seeds, peel the skin off and cut it into the fruit. You will see lots of tiny seeds and one fruit should provide you with sufficient seeds to begin growing the following year. 

Opuntia humifisa seeds require moisture and shade to germinate. The seeds will need to ripen before germination.

Overwinter in a cold, dark place till spring and keep them in a container that is completely closed and airtight.

Nighttime temperatures should be consistently 45°F (7°C) or above before you plant your seeds.

Fill small pots with cactus soil. It’s important that the vessel you use drain well. Water thoroughly and allow the soil to drain.

Before planting, rub each seed against a rough surface to scratch the outside of it. This will speed up the germination process.

Plant one seed in each pot. If using a seed tray, space the seeds roughly  1” (2.5cm) apart. 

Cover the seeds with an inch of soil and press them into the soil slightly.

Mist the surface of the cactus soil and then cover over with clear plastic. You will need to make a few tiny holes in the plastic for ventilation.

The pots or trays should be placed on a windowsill where they will receive direct sunlight. Alternatively, you can place them under artificial lights. 

The soil should remain moist and should be kept at a temperature of 70°F (21°C). If the soil dries out, mist it again to keep it moist but not wet.

If the temperature under the clear plastic goes above 70°F (21°C), remove the cover to allow some of the heat to dissipate.

Opuntia humifusa seeds can be erratic and it may take anywhere between 1 week and 6 months for seedlings to appear.

Once they do sprout, it’s important to monitor your seedlings daily. If they begin to turn yellow, they need more light.

If they are getting too much light they will go reddish brown. Your seedlings are ready to be handled once they are a healthy green color and around 3” (7.5cm) tall.

When transplanting your seedlings, space them around  3ft (90cm) apart in an area where they will receive full sun.

You will need to keep the soil moist for the first 2-3 weeks while the plants become established.

Once they are established, gradually increase the time between watering and start to allow the soil top dry more to get them used to their natural habitat.

If you plan to keep your plants indoors in pots, follow the same pattern of keeping the soil moist for the first 1-2 weeks but as conditions will not be so harsh, they should become established more quickly.

Growing Opuntia humifusa from seed is a labor of love and it can take 3-4 years before your new plants produce flowers or fruit.

Propagation from pads produces much faster results.

Once pads are 6 months old they are mature enough to be pruned and transplanted. For best results choose a pad that is at least 10cm (4”0 long.

Remove the entire pad by snapping it using gloved hands. Each pad should be placed on a windowsill or other surface where it will receive direct sunlight until the ‘wound’ has healed over.

This way there is little chance that the cactus will start to rot. The healing process can take up to 4 weeks but it’s important you don’t become impatient and plant your pads too early while they are still susceptible to rotting.

Once the wound is calloused over, plant each pad in a mixture of 50% sand and 50% cactus soil to a depth of  1” (2.5cm).

You may need to prop your pads up at this stage until it forms roots to hold itself upright. Your new plant should be able to stand up on its own within a month. 

During the first month, don’t water it. There is sufficient water in the pad itself. 

Once you start to water your plant, be sure to not overwater and allow the soil to dry out between waterings. 

If you plan to plant your new Opuntia humifusa in the garden, you can do so once the roots have formed.

Keep the soil around them moist for the first two weeks in the same way that you would when planting out seedlings.

Space your pads around 3ft (90cm) apart in an area where they will receive full sun.

Once established, you can expect flowers and fruit to appear after your new plant has grown its third or fourth pad.

 

Common problems with Opuntia humifusa

Although it is a sun-loving plant, Opuntia humifusa can suffer from sunburn if it is moved to a full sun position without being acclimatized.

Sunburned Opuntia humifusa will go yellow and, if left untreated the affected parts of the plant will die.

Placing cheesecloth over newly positioned plants can help protect them. Ideally, new cacti should be gradually introduced to full sun over a period of 2-4 weeks. 

Overwatering any cacti can cause root rot or scab. Scab appears as rust-colored, rough corky areas or lesions on the stems.

Scab is a predominantly aesthetic problem that should clear up by establishing a more appropriate watering schedule. 

Opuntia humifusa is susceptible to spot diseases such as Phyllosticta pad spots or charcoal spots, both of which manifest themselves as dark spots on the pads.

Anthracnose is a fungal infection that can attack Prickly Pears too. If your plants are infected with anthracnose, you will see a moist light brown rot with light pink pustules. 

All three of these are untreatable and infected plants should be disposed of to prevent further spread. 

 

Frequently Asked Questions About Opuntia humifusa

 

Are the fruits of Opuntia humifusa edible?

The fruits are known as Prickly Pears and are perfectly edible. They taste similar to strawberries or raspberries.

 

What is the white sticky stuff on my Opuntia humifusa?

It is most likely cochineal, a sucking insect that feasts on the juice of cacti. The white sticky substance protects it from predators. Dabbing the infestation with a solution of 1 part rubbing alcohol to 3 parts water will get rid of them.

 

How long does Opuntia humifusa live for?

They have been known to live for over 20 years if kept in the right conditions.


 

Conclusion

Opuntia humifusa is a great choice for the beginner cacti grower as it is so easy to look after. You are more likely to cause your plants problems by doing too much rather than too little.

Applying too much water or fertilizer is both likely to cause harm. Opuntia humifusa is a hardy plant that will cope well with extremes of weather and still thrive when conditions are right.