Planting Out of Season

 In My Trade

Ryan Simpson, Horticulturist and Sales Manager for Viridis Plants, explains how with the right considerations, plants can be successfully planted out of season in the summer months.

We all know the drill: plant perennials and spring bulbs in autumn, hedges and trees in winter and summer bulbs, annuals, and later flowering perennials in spring. These horticultural commandments have been the basis of our planting calendar since we lifted our first trowel. Summer is a season we daren’t plant in – we fear the endless heat and sunshine will wither our precious young plants but is this really the case?

magenta coloured dahlia being visited by a honey bee

Rootballed vs Container Grown 

A few things are unnegotiable. Trees and shrubs that are field grown should only be lifted when dormant and not in active growth. For deciduous species, this means when their leaves have fallen. Lifted plants with a decent sized rootball are subsequently protected from the wind and extreme temperatures, so can be planted right up until May and beyond.

Container grown stock such as trees, shrubs and perennials can continue to be planted throughout the year, you just need to prepare the soil to establish the plants correctly.

Planting conditions and aftercare are so much more impactful than planting timings, so what can you do to assist the establishment of soft landscaping planted over the summer months?

Right Plant, Right Place

penstemon planting in a large group for maximum impact

Before you consider any planting (at any time of the year), it is important to remember that even the most pampered plant, if planted in the wrong location, will never thrive. 

Pick the correct plant for the conditions present, and all other elements should fall into place.

Soil Preparation

Once you have selected the correct plant, the condition of the soil will be the factor that has the most impact on your level of success. The main issues with soil are often poor drainage or poor water holding capacity (which can also lead to poor nutrient availability).

The solution for most soil problems is organic matter – and a lot of it. Organic matter will hold water and nutrients in sandy, free draining soils, and allow water to percolate through heavy clay soils.

Before planting, make sure that sufficient organic matter has been applied to the entire bed and that cultivation has been deep enough to fully incorporate it into the soil.

During planting, fill your planting holes with water before placing the plant within them. This ensures there is a ready supply of moisture at the roots. Water and firm every plant in thoroughly, to encourage the soil to settle closely against the roots, removing large air pockets which could quickly dry them out. Finally, mulch with a minimum of 10cm of well-rotted organic matter to seal the moisture in, taking care to avoid mulching right up to the stem or crown of the plant. 

Watering to Establish Planting

water cascading from the rose on an old fashioned metal watering can

After planting, water regularly. It is most effective to water slowly at the base of a plant less often, to encourage the plant’s roots to extend and establish deeper into the soil. The aim should be to water between 1-2 times a week during summer months. An average sized tree will need 90-100 litres of water a week during the first 3-5 years of its life – that’s 10 watering cans per tree! By watering in this way, you will create a well-established plant that can survive most heatwaves.

Given this degree of care, and assuming you have positioned plants to suit their preferred light levels and given them sufficient space to grow, there is no reason why summer planting can’t be as successful as planting carried out in spring or autumn.

Viridis Plants

summer planting of crocosmia Lucifer

Viridis are specialists in growing, sourcing and supplying premium quality plants for garden designers, landscaper and architects. Our in-house production is complemented by our extensive sourcing capabilities to meet the expectations of discerning customers wanting the best and most unusual plant varieties for their bespoke designs. We work with designers and landscapers across the UK, providing a superior and exclusive level of service. We are a customer-focused team and invite you to send your planting requirements for quoting by our horticulturally trained sales team. 

Furthermore, we offer a wide range of information to garden designers, landscape architects and horticulturists through our ‘Plants for Purpose’ series, overcoming a wide array of garden conundrums with curated suggestions for problem areas.


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Follow these links for some more great plant related blogs

Planting with purpose – guest blog from Viridis Plants

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