Current Issues, Jorge, Plants

A 1644 edition of Theophrastus’ Historia Plantarum.

Plant taxonomy, or systematics, is one of the oldest biological disciplines, tracing back thousands of years to when the identification of medicinal, edible, poisonous plants as well as those suitable for crafting would prove essential for survival and later man’s mastery over the environment.

Paradigmatic to history of science were the ideas of Aristotle, in particular the science of logic. This method influenced systematists who sought to identify the essence of living things by examining many specimens and discarding variable characteristics and establishing constant characteristics. This, of course, does not work well for biology with species exhibiting significant variation between individuals. Thus, improved understanding required the emergence of empiricists, who did not believe in the essence of each form.

Other early historic figures include Theophrastus and Dioscorides, who were both Greek, but lived hundreds of years apart in classical Greece and the Roman period respectively. Theophrastus wrote hundreds of manuscripts describing plants including two large botanical treatise Enquiry into Plants and On the Causes of Plants. His works are the first surviving documents to describe plant parts, reproduction and sensitivity to climate as well as classify them by their properties as medicinal, edible and herbal for example. Dioscorides travelled widely as a physician in the Roman army and classified over five-hundred plants by their medicinal properties in his five volume De Materia Medica. Unlike Theophrastus, whose work was lost to the West till the renaissance, Dioscorides’ pharmacopoeia remained the primary botanical text for nearly fifteen hundred years.

Aristotle made immeasurable contributions to numerous fields. Despite this, many of his scientific ideas were off the mark and became entrenched after becoming part of Church’s official doctrine, which sent thinkers down blind alleys and forbade freethinking.

It took to the 1600s for the next major advance in taxonomy with John Ray’s Methodus Plantarum Nova that published details of eighteen thousand species classified by their morphology – that is an organism’s form and structure. Previously, many taxonomic systems were arbitrary, sorting plants alphabetically or by their medical properties; although he has an interesting precursor in Andrea Cesalpino, who classified plants according to their fruit or seeds. Ray was devoted in his study of botany and based his system on all of a plant’s structural characteristics, including internal autonomy. He was also a cleric and can be viewed as an early parson-naturalist who saw science as an extension of his religious work, with God wishing for man to understand his creations by collecting and classifying organisms.

Next came Joseph Pitton de Tournefort’s Eléments de botanique, ou Méthode pour reconnaître les Plantes that while not particularly original and somewhat flawed was both well written and structured and would prove highly influential as an educational textbook, especially for the father of modern taxonomy Carl Linnaeus.

Linnaeus proved revolutionary, creating the taxonomical system in use today, laid out in the works Systema Naturae and Species Plantarum. He established the binominal system of nomenclature – that is, the use of a two part name for each species, consisting of the genus name and scientific epithet. This proved a huge advance over the long, excessively descriptive names used previously such as Rosa sylvestris inodora seu canina and Rosa sylvestra alba cum rubore, which now read simply as Rosa canina. It was in fact essential with the massive influx of species originating from the hitherto unexplored regions of Africa, Asia and the Americas in need of classification.

(These older names were influenced by the Aristotelian definition of form, split into genus – the general thing described – and the differentia, which gave its special characteristics. The major problem with this was as more species were discovered the differentia became longer and longer, hence the impractical name for the dog rose above.)

John Ray saw the natural world as static, its wonders evident of intelligent design.

The publication of Charles Darwin’s The Origin of Species and his theory of evolution would again prove paradigmatic. Classifying plants by their morphology was clearly limited as organisms can possess similar characteristics but be unrelated. It was now the task of systematists to use classifications to reflect evolutionary history, placing closely related organisms together, and identifying unique species.

It wasn’t until the 1960s that systematists could accurately classify organisms according to their evolutionary history with the work of Walter Zimmerman and Willi Hennig in the preceding decades that established an objective criteria for determining the shared genetic attributes of living and fossil organisms. It was in this decade also that revolutions in molecular biology provided methods for determining the molecular structure of proteins and amino acids. It was techniques such as these that allowed systematists to supplement their analysis by comparing organisms’ genetic codes and identifying changes in genetic code.

Today systematists use multiple sources of evidence to establish a plant’s evolutionary history such as morphology, biochemistry, paleobotany (plant fossils), physiology (internal activities – i.e. photosynthesis), ecology (plants and their environment), biogeography (plant distribution), and molecular systematics (analysis of genetic code). This has been enabled with advances in computing that have allowed the analysis of large datasets.

Carl Linneas characterically posing with a plant.

Scientists estimate that there are ten to one hundred million species, so establishing their evolutionary history is a monumental undertaking. Currently, plant taxonomy is controlled by the International Codes of Botanical Nomenclature (ICBN) published by the International Association of Plant Taxonomy (IAPT), who revise codes at every International Botanic Congress. It should be stated that even with all the advances in understanding, scientists still disagree how to best classify organisms. For example what is a species?

One definition, known as the Biological Species Concept, defines a species as a “group of similar individuals which can reproduce successfully with each other while at the same time being reproductively isolated from other similar species”. The problem with this is identifying the point at which a particular population is distinctive from its parent species, as there are infinite possibilities to choose. Another definition, known as the Phylogenetic Species Concept, places more weight on the genetic differences between populations and their evolutionary history. Again the problem with this is that scientists can identify numerous genetically distinct populations, greatly increasing the number of known species.

To conclude, plant taxonomy is an ongoing project that will likely never end due to divisions about the importance of a particular characteristic and the discovery of new species and fossils. Nevertheless, the work to date has produced a logical system of classification that makes identifying plants and their relatives relatively easy.

If you would like to know more about the challenges of classification a great overview can be found here. If you would like a simple overview of the classification of plants, a table can be found here. If you would like to know more about taxonomy, especially the ranks you are likely to come across  when browsing for plants, please read our article: What is the Difference Between Genus, Species, Variety and Cultivar?

Jorge at PrimroseJorge works in the Primrose marketing team. He is an avid reader, although struggles to stick to one topic!

His ideal afternoon would involve a long walk, before settling down for scones.

Jorge is a journeyman gardener with experience in growing crops.

See all of Jorge’s posts.

Amie, Barbecues, Fire Pits, Lighting, New Products, Outdoor Heating

The sun is setting, and the evening is cooling.
The sausages upon my BBQ have left me drooling.
With water and squash, and a dash of fizz,
Topped off with cake, this evening is bliss.

The wood upon the pit is crackling for hours,
Alongside the beauty of the summery forest flowers.
Easy to construct, robust and sturdy,
We’ll be sitting by the firepit until at least 1130.

The next morning has come, and it’s time to clean,
Which is easily done, now my firepit is pristine.
Back into it’s zipped bag, stored away for now,
My Primrose Firebowl has been has been nothing short of wow.

Get yours for only £39.99, with next day delivery available.

AmieAmie is a marketing enthusiast, having worked at Primrose since graduating from Reading University in 2014.

She enjoys all things sport. A keen football fan, Amie follows Tottenham Hotspur FC, and regularly plays for her local 5 a side football team.

Amie also writes restaurant reviews on Barnard’s Burger Blog.

Gardening, Jorge, Planting, Trees

Before we continue, it should be stated that while bare root and containerised trees each have their own advantages and disadvantages, they will not significantly affect a tree’s health, so you can be happy knowing your tree will one day achieve its potential. Rather, it is your own preferences regarding price and time of planting that will make an option worthwhile.

What’s the difference?

Containerised trees are supplied in containers, while bare root trees are supplied without soil with their roots carefully wrapped in plastic. Trees can only be extracted from soil when they are dormant; dormancy occurs from late-Autumn to early-Spring when the tree sheds its leaves. Depriving a tree of nutrients during Spring and Summer is highly detrimental to its health as the tree will try to grow, but be unable.

So this is where the first difference is. Bare roots can be supplied only when the tree is dormant, while containerised can be supplied and planted anytime during the year. (Although, it is worthwhile to first research the time of year a particular species best establishes itself. And, in general, it is not recommended to plant trees in summer when they grow at their fastest rate as without established roots, it may fail to establish.)

As bare roots are supplied without soil, they are lighter and cheaper to transport, which makes them significantly cheaper (30-50%) than potted varieties. Hence, bare roots can be great value for money.

Next, as bare roots grow in the ground, their roots spread out in a natural fashion, which allows them to establish themselves effectively, giving them adequate access to soil from which they acquire their nutrients. Sometimes a containerised plant’s roots have inadequate room to grow, resulting in spiralisation, whereby their roots grow in spiral at the bottom of the pot, which puts it in a poor position come planting. Although, this usually only occurs in garden centres, rather than nurseries that will upgrade a tree’s pot as it ages.

It has been argued that containerised trees are better at establishing themselves when planted as they are supplied with nutrients throughout the transplanting process. Bare roots, on the other hand, often lose a chunk of their roots when transplanted, which can lead to water stress. However, this argument doesn’t really hold up, because the tree’s roots are wrapped with compost or hydrogel. Furthermore they are usually supplied as one or two year old trees, which ensures the roots are adequate for the above-ground matter. Altogether, providing the tree is well wrapped and planted promptly, it will be fine. If you can’t plant immediately, it is recommend to leave the tree in water, possibly with the addition of liquid fertiliser.

Planting trees is not recommended in Summer, nor when the ground is frozen, so containerised can’t be planted anytime and it is recommended to buy bare roots when they are first available in November.

This leads to another advantage of containerised trees: they do not have to be planted immediately. This can be useful if you wish to gift a tree. And as containerised can be purchased whenever, you can purchase a deciduous in summer when it looks best. Furthermore, containerised are pruned so will have a nice shape on arrival. Bare roots on the other hand aren’t, which on-the-flipside can be useful if you wish to train a tree, as in the case of many fruits. Lastly, there are many options of containerised trees. One can purchase, for example, a 9 year old ornamental in 55L pot that can provide an immediate uplift to a garden.

Overall, all trees will flourish, providing they are looked after. Bare roots are cheaper and can be trained into a fan, espalier or cordon, but they are only available as one or two year old trees and can only be planted in the Winter. Containerised trees can be planted whenever, look better on arrival and come in a range of sizes, but they are more expensive and can be harder to train.

Have you decided on a bare root or containerised tree? If so, Primrose has a huge range of fruit and ornamental trees, both bare root and containerised, so please have a browse.

Jorge at PrimroseJorge works in the Primrose marketing team. He is an avid reader, although struggles to stick to one topic!

His ideal afternoon would involve a long walk, before settling down for scones.

Jorge is a journeyman gardener with experience in growing crops.

See all of Jorge’s posts.

Gardening Year, How To, Liam, Planting, Plants, Trees

How to plant bare root tree

Planting a tree is a decision made with many, many years in mind. With that being said it is essential to give your young tree the best possible start so it can grow to its full potential. With this guide we will show you you how to plant a bare root tree, which, like most plants, requires some initial TLC.

 

Bare root trees are uprooted and sent out around November to March, while the tree is dormant. Therefore it is around this time you’ll be planting them, however, avoid days when the soil is frozen or waterlogged.  

On receiving your bare root tree you will want to plant immediately. If this is not possible then it is essential to check the roots to see whether or not they have dried out. If they have then dunk in a bucket of water for 5 minutes and then return it to the plastic packaging, making sure it retains its moisture.

Giving the Roots a Soak Before Planting

The tree’s nutrients are critical to the survival of the tree and its ability to establish itself are stored in the roots. When the roots dry out the tree will suffer severe damage and may even die. For this reason it is a good idea to soak the roots in a bucket for up to 30 minutes before planting. Equally the tree needs to breath and so leaving it in the bucket for much longer will suffocate it.

When picking a site for your tree, ideally you will want somewhere which is going to receive full sunlight and will be sheltered from harsh, drying winds. Make sure you pick a spot where the roots will have a chance to grow and spread out. If training against a wall then leave at least 1ft of space from the base of the plant.

Dig a hole with a diameter roughly 3x the size of the roots and with the same depth. If planted too deep, the lower trunk of the tree may become susceptible to disease. The graft-point of the tree should be above the soil. 

A square hole allows for the greatest root penetration and growth. Loosen up the soil at the bottom of the hole with a fork and also the sides if they appear compact.

The Correct Size and Depth of the Hole Relative to the Roots

You can plant a stake by the side of the rootball to give the tree some additional support if required. For a bare root tree we only recommend using one stake as their roots are more spread out. If planted in a sheltered site it may not be required and we advise not using a stake to improve the tree’s strength and flexibility. See our guide to staking a tree.

Take the soil you have dug and mix in compost so that it is three parts original soil, one part compost. You can add some further compost to the bottom of the hole and then fill in with your soil. There is no need at this point to apply a fertiliser, you can however sprinkle around the roots with mycorrhizal fungi (Rootgrow) to stimulate root-growth.

The Hole Filled in with Stake in Place

Place your tree in the hole and then fill in with your soil. Every now and then gently heel in so that the soil is touching the roots. Air circulation is essential so don’t compact the soil too much.

After this form a bowl with the soil around the tree and fill with water. This will ensure the water doesn’t spill off and go directly to the roots. In the first few years it is important to look after and regularly water your young tree, especially through periods of extended heat. Once the roots have grown out and the tree has established itself it will require less maintenance.

Liam at PrimroseLiam works in the buying team at Primrose. He is passionate about studying other cultures, especially their history. A lover of sports his favourite pass-time is football, either playing or watching it! In the garden Liam is particularly interested in growing your own food.

See all of Liam’s posts.

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