Having non-invasive and relatively shallow root system, makes pomegranate trees suitable for growing in containers and flower pots. Large varieties of pomegranates can grow up to 6m (20 feet), however, there are varieties that grow 1-2m (3-7 feet) or even less in height.
Blooming pomegranate tree is great addition to any garden and many people grow them not only for their fruits, but also for their flowers. Such ornamental trees, with strong contrast between dark, green leaves and strong orange-red flowers are often used for landscaping and as decoration. Orange, pink and red fruits later continue to contribute to the garden appearance.
Pomegranate Root System
Pomegranate root system is shallow, with most of it being less than 60cm (2 feet) deep and very rarely below 90cm (3 feet) - large, mature trees or strong, wide shrubs. For growing in containers, this is beneficial in many ways: containers don't have to be extra large, can be wider than higher which makes plants and containers more resistant to wind, easier maintenance etc.
Note: when growing pomegranate on permanent position, knowing characteristics of plant's root system is very important - shallow root system reacts faster to watering and fertilization and being resistant to drought, makes requirement for deep root system unimportant.
In fact, pomegranate is sensitive to soggy and damp soil - such growing conditions can lead to flower and fruits loss and to low fruit quality. In the long run, such conditions even can kill pomegranate tree.
Proper Soil and Watering
Pomegranate tolerates poor soil quality and various pH. Best growing conditions are around pH 6.5 - 7, however, it will happily grow anywhere between pH 5.5 and 8, even outside these boundaries.
Growing plants in containers provides gardener with the opportunity to match 'perfectly' soil characteristics for pomegranate. So, fill the container with a good potting soil, add dried manure pellets (doesn't have to be dried manure pellets, but I use it often instead of 'classic' manure), add some balanced NPK fertilizer 8-8-8 or similar, add some compost and humus, add shovel of sand, add shovel of hydroton pebbles, mix everything and plant the pomegranate tree. Ideal time for planting is late winter when plants are still dormant, however, being resilient as it is, carefully replanted pomegranate will established them quickly and grow easily on the new spot.
Also, be sure to check pH of soil from time to time, since many fertilizers increase acidity slightly over time.
- hydroton pebbles are great for retaining water and they help soil to 'breathe'. As plants take water in or as water evaporates, air enters the soil and helps it keep oxygenated. Very important for keeping plants watered longer and for healthy root system. Also, hydroton pebbles in combination with sand, help draining any excess water.
- I never tried adding hydrogel beads or powder to pomegranate containers and I am not sure that that would be a good idea - hydrogel 'suck in' water and release it into the soil again, but hydrogel changes its volume without helping soil to 'breathe'. To really test hydrogel, one needs several plants and several years - if you have tried it, please, give us a note.
- dried manure pellets are strong fertilizer and with or without NPK fertilizers, can cause root burns. Apply it carefully, around the rim of containers, not close to the tree trunk. Personally, I would recommend adding fertilizers on monthly schedule, but in small amounts. This avoids nutrients spikes, decreases potential root damage (burns!) and gives gardener opportunity to more often 'feel' the plant and soil.
Water pomegranate in containers whenever you water your other plants, just keep the amounts of water moderate - normally, pomegranate trees require around 2-3 cm (1 inch) of water, weekly, but this slightly increases when growing them in containers.
Also, organic mulch can help - it will decrease moisture loss and will gradually release nutrients into the soil. So, add or keep 2-3 cm (1 inch) of mulch on top of the soil to help the plants stay healthy, grow, flower and bear fruits.
Pomegranate Container Size and Type
Size of containers depends on desired size and variety of pomegranate tree/shrub. Actual size of containers depends on time that gardener has for such plants - larger containers requires less frequent watering, for example.
For shrubs and trees up to 2m (7 feet) high, 75cm (2.5 feet) wide and 60cm (2 feet) high containers are more than enough - this is for mature trees or shrubs bearing fruits. For ornamental only varieties, containers can be smaller. Wider containers are also more stable to gusts of winds or running kids and pets (been there, seen that!). When tipped over, larger containers are also harder to return to standing position, requiring some decent strength. Also, repositioning of larger containers is harder than smaller containers - very important if you have to protect/reposition your pomegranate plants during winter.
Most people grow pomegranate in plastic containers, but other materials are also used - ceramic, terracotta, concrete etc.
However, one of the most important aspects of a good growing container for pomegranate is - drainage. Be sure that on the bottom of the container there are more than enough holes to let any excess water drain away. In fact, some people grow pomegranate in containers without base plate, so that there are absolutely no retained water in the container.
If you have base plate with wheels (or wheeled base) and you are afraid of excess water damaging your plants, but you still want to have container on the base plate with wheels, simply make enough holes in the base plate AND in the containers bottom - such base plate with wheels is excellent option for plants that need repositioning.
Dwarf and bonsai pomegranate trees can be grown in ordinary plastic flower pots and maintained just like larger pomegranate varieties, except that they need more frequent watering during summer heat.
Small, Dwarf and Bonsai Pomegranate Varieties
When choosing variety for growing in containers, be sure to pick the variety that has wonderful flowers, but also bear edible fruits. Unless you really, but really don't like pomegranate :)
'Wonderful' variety grows as small tree or a shrub and can be successfully grown in the containers. Also, be sure to check varieties like 'Nana' (dwarf, 2-3 feet high), Angel Red, Parfianka, Red Silk, Pink Satin, Sharp Velvet etc. Also there are interesting varieties like Haku-Botan or Toyru-Shibori - I never had any of these two, but I will give them a try one day :)
Pomegranate Tree Care Tips
With stronger pruning, one can and should keep the size of the pomegranate tree/shrub under control. Be sure to remove anything that is ill, broken, damaged or that is outside of desired proportions.
Pomegranate are very resilient to pests and diseases, regardless if they are grown in containers or on soil patch.
Pomegranate butterflies are only common in certain regions - to keep them under control, one has to spray before they lay their eggs. Against aphids, mealy bugs, thrips, whiteflies and other bugs one can use soapy spray or other organic insecticide. Dusting the tree with some sulfur in June and again in July can help against mites.
Position container with pomegranate on full sun. Pomegranate will tolerate partly shade, but they really like the sun. Having wheeled containers helps a lot when having larger plants.
Most of the pomegranate plants are self fruitful (self pollinating), requiring no more pomegranate plants. However, cross pollination often leads to larger crops and if you can, grow several plants near by.
Most pomegranate varieties don't require winter chill hours, except some cold-hardy varieties. However, they can only benefit from 150-200 hours of low, but not too low temperatures. Chill hours are winter hours when temperatures are below 0 and 7°C (32 and 45°F), but this definition differs. Generally, pomegranates can survive up to -10°C (14°F), but such prolonged conditions can cause damage to the roots of plants growing in containers with exposed container sides. Obviously, protecting containers with plants during winter from cold winds is very important.
It takes sometimes 5-6 years for a pomegranate to starts to bear fruits, so be patient.
Growing them in containers, even in green house if you live far to the north (or to the south, if you are 'down under'), enables one to enjoy this great plants without much care and effort.