In this post we discuss the growing of plants in pots and containers. The ability to move a plant in its pot, the growth of potentially special plants in containers, some more advantages and disadvantages and the choice of materials for plant pots are also covered.
Portability of Pots
For an increasing number of householders, containers form their only garden space. Millennials in rented accommodation, if lucky, may have access to a garden but its structure and layout is unlikely to be in their control. Containers allow personal plant preference and design, and if there is a change of circumstances they can also be moved with all the other household belongings.
This portability though is useful for all of us that grow plants in containers.
Plants such as herbs can be grown in pots near the door for ease of access.
Sometimes screening is required for a site with no available planting space. Ugly pipes can be disguised behind foliage at eye level using pots instead.
Some half hardy plants can be brought near the house in winter to give them the benefit of radiated heat from the house walls and shelter from the worst of the wind and wet. This has allowed these Pelargoniums to stay in pots outside over these last few milder winters.
Manipulation of growing conditions and compost.
This old sink was removed from the cellar kitchen when we moved in 30 years ago. It sat around for years unused but recently it was planted up with alpine and succulent plants as shown. Generally garden soil is too rich and heavy to grow succulents like house leeks (sempervivums) and this small plant would also quickly get swamped by other plants. In a container it can be displayed and the growing medium can be changed to conditions that suit the plant. The small Sedum is quite happy in the same gritty compost as the sempervivums. The Sisyrinchiums are in a richer pocket of soil (blue flowers).
Sometimes plants need soil conditions that your garden cannot offer them. Most heathers or rhododendrons need a soil with an acidic pH. Pots and containers are the answer if the garden soil is neutral or alkaline.
Pots are really useful to grow fruit and vegetables if there is no room to grow them in the garden.
One of the best shrubs to grow in an ericaceous (acidic) compost is a blueberry. It’s actually better to grow two to promote cross fertilisation and get better yield of berries. They do like moisture and watering with rainwater is preferable because of the preferred pH range. Apart from the berries the autumn colour in the foliage is an added bonus. Rogers of Pickering offer a good range of plants.
Shrubs in pots generally do better in a soil-based compost. John-Innes composts are a loam (soil) based range of composts eg. John Innes No1,2 or 3. The standardised mix of ingredients have increasing amounts of fertiliser and for shrubs JI No3 is advisable.
Most plants however do well enough in multipurpose, peat free compost as long as they are fed every week or so in the growing season. A top dressing of fresh compost in spring also helps.
Some plants should be contained.
Pots should be used to contain certain roguish plants. Equisetum hyemale or ‘rough horsetail’ is one such plant although it isn’t as bad as some horsetails. In days gone by it was used to clean pots as its stems contain silica. It’s well worth growing for that evergreen upright form.
Another common plant to grow in a pot and not in the border, is mint. This herb will take over the whole of your border given the chance!
Other Advantages and some Disadvantages of Pots.
Containers and pots permit easier access to the plant by lifting the soil level making maintenance simpler. Weed growth in a pot is also much less likely and easily dealt with. Other advantages include better protection from some pests. Rabbits are surprisingly easy to confound by pots over a couple of feet high. Slugs and snails can be spotted more easily. One pest to watch for is vine weevil which does more harm in pots than open ground. Once the adult weevil has spotted that Heuchera or Primula in a pot, she’ll lay her eggs for the larvae to do their worst. You notice the plant has collapsed and on further exploration the top growth just detaches from the roots which have been completely decimated by the larvae. A preventative nematode wash is the best treatment option, and is easily watered over susceptible plants.
Pots can also protect plants against a pet or even the football!
Disadvantages of containers are primarily because of the restricted root run given to plants. The limiting amount of growth medium means nutrients are quickly used up. The increased need to water also results in leaching so there is a need to fortify the compost after about six weeks. Plants will eventually outgrow a pot and the pot size can be increased, the plant transplanted to another area of the garden or the gardener may choose to root prune the plant.
There are many suppliers of some really beautiful pots. The pot has to be appropriate for the site and aspect. Containers made from lead are traditional and beautiful but unfortunately theft is a real issue and if there is a risk then a substitute material that mimics lead is a better choice.
Lightweight materials are also more appropriate on a balcony where loads have to be carefully assessed. This has to be balanced by the effects of the wind and containers must be fixed securely. Metal containers heat up quickly compared to pot and terracotta and roots may be easily scorched. The use of some insulating material such as wool will help keep the root ball cool and moist. Terracotta is a good choice as it is generally cheap, appropriate to most styles and also sustainable. Frost hardy pots are safe to minus 10C and in winter should be put on raised feet to reduce the risk of cracking.
In this garden pots provided additional planting opportunities.
Containers can be made the main feature of a garden space.
This impressive pot was at Wynyard Hall and almost a metre high.
Garden designers often have trade accounts that enable them to access a wide choice of pots and get a good deal for their customers.
What pots and containers allow is experimentation and creativity, where displays of plants can be changed regularly to reflect the seasons. Most gardeners find there is great fun in mixing and matching plants and pots to keep a display interesting and joyful through the year.