How to Save a Plant With Root Rot?

What is root rot?

What is root rot?  Ι   Causes of root rot  Ι   Signs of root rot  Ι  How to inspect the roots for signs of root rot  Ι  How to save a plant with root rot  Ι  How to prevent root rot in plants

What is root rot?

Root rot is a condition characterised by the decay and death of plant roots with two primary causes; not enough oxygen (anoxia or hypoxia) or bacterial, viral, fungal and water mould infection. Because root rot occurs beneath the soil, a considerable amount of damage can occur before it is noticed.

Read more

What Are Plant Bulbs?

What are plant bulbs?

What are plant bulbs?  Ι   What are the five types of bulbs?  Ι   What is the purpose of bulbs?  Ι   Can you grow bulbs in pots?  Ι   How deep should bulbs be planted?

Key points

  • Plant bulbs are storage organs that allow plants to store nutrients and energy during unfavourable conditions. They are composed of modified leaves and are usually spherical or oblong in shape.
  • Bulbs are a type of geophyte, which means they are plants that have an underground structure that allows them to survive periods of dormancy and unfavourable conditions.
  • There are five types of bulbs; true bulbs, corms, rhizomes, tubers and tuberous roots.

What are plant bulbs?

Plant bulbs are a perennating organ made up of a modified stem and/or leaves. A perrenating organ is a specialised plant structure adapted to store energy in the form of carbohydrates, and water, allowing the plant to survive from one germination season to the next. These food reserves sustain the plant through a period of dormancy and re-emergence.  When environmental conditions are right, the bud within the centre of the bulb emerges.

Several types of storage units exist in the plant kingdom which includes true bulbs, tubers, rhizomes, corms, and tuberous roots. All bulbs are adapted to survive periods of dormancy during unfavourable growing conditions. At these times, the bulbs’ energy-storage organs sustain the plant through a period of dormancy and re-emergence. When environmental conditions are right, the bud within the centre of the bulb emerges.

Storage organs can be either bulbs, corms, rhizomes or tubers. Bulbs are more common in temperate regions and among monocotyledons (plants with one seed leaf), while rhizomes and tubers occur more often in tropical regions and among dicotyledons (plants with two seed leaves). The main difference between bulbs, rhizomes and tubers is how they are organised internally.

Most plant bulbs are perennial, which means they come back every year. However, growers in warmer climates will need to chill certain bulbs native to cool areas (hardy bulbs) such as hyacinths, to trigger the development of the flower bud within the bulb. The chilling period is approximately 12 weeks to mimic the winter season.

What are the five types of bulbs?


True bulbs

These are bulbs with a short stem with a growth point that is enclosed in a thick, swollen leaf base (known as scale leaf). True bulbs fall into two groups, tunicate bulbs and imbricate bulbs. Tunic bulbs such as the onion or daffodil contain a papery ‘tunic’  outer layer to protect the delicate scales, while imbricate bulbs such as the lily do not have the tunic and therefore must stay moist prior to planting out to prevent damage to the scale leaves.

  • Basal plate: The compact, modified stem from which the root and flowering stem and new buds grow)
  • Scale leaves: Primary storage tissue and modified leaves
  • Tunic: The thin skin-like covering that protects the fleshy scales
  • Shoot: Consists of developing flower and leaf buds)

Plant bulb anatomy

Common types of true bulbs include the Dutch iris, daffodil, tulip, hyacinth, grape hyacinth, snowdrop, amaryllis, garlic and alliums.

Bulbs are categorised according to their hardiness.

  • Hardy bulbs such as snowdrops, crocuses, grape hyacinths, tulips and daffodils are able to withstand cold winters. In fact, some hardy bulbs need a cold period to break dormancy, which is why some bulbs are placed in a refrigerator prior to planting out. Hardy bulbs contain antifreeze to prevent the formation of ice crystals within the bulb during sub-zero temperatures. These types of bulbs are some of the earliest flowering plants in spring. The tips of snowdrop leaves have a hardened tip to break through frozen soil¹.
  • Semi-hardy bulbs can tolerate some cold but require some protection.
  • Tender bulbs cannot tolerate freezing and must be lifted in cold climates.


Tuberous plant

Tubers are thickened modified plant stems or roots, used as storage organs. Unlike the true bulb, tubers are made up of starch-storing parenchyma tissue and do not contain the basal plant within. The rhizome contains eyes that eventually produce shoots above ground and underground roots. Potatoes, cyclamen, dahlia, and caladium are all tuberous plants.



Also known as a creeping rootstalk, rhizomes are underground horizontal plant stems that grow just below the surface of the soil. Rhizomes contain the same internal and external structures as stems. Growth points known as nodes are present along the rhizome which are growth points that develop into leaves and flower stems. Common rhizomatous plants include the bearded iris, ginger, turmeric, canna lilies, snake plant and bamboo.



Corms are swollen stem bases that act as organs for nutrients. They are similar to bulbs but lack fleshy layers. Corms have a single vascular bundle (the bundle of xylem tissue that conducts water and dissolved minerals up the stem), compared to bulbs which have two separate bundles. At the top of the corm is the growing point (bud), where the leaves and flowers develop, the base has a basal plate, from which the roots develop and the entire corm is surrounded by a thin tunic. Examples of corms include gladiolus and crocus.

Tuberous roots

Tuberous roots are thickened roots that hold food sources. Examples of plants with tuberous roots include the begonia, spider plant, peonies and daylilies.

What is the purpose of bulbs?

Hormones and environmental factors (light, temperature) trigger dormancy or release dormancy. Leaf tips erupt from the neck of the bulb and quickly grow, followed by the flower. Once the flower is spent, the foliage dies back over a period of several weeks and the plant re-enters dormancy. While the leaves are dying back, the bulb gathers energy to store by photosynthesis, which is turned into plant sugars. Gardeners should not cut back the foliage after flowering has finished as this removes the ability of the bulb to store energy for the dormant period and the following year’s growth. Foliage can be removed once it is yellow or brown.

If bulbs are not allowed to develop a strong root system, the bulbs will produce fewer blooms and be more susceptible to disease. Bulbs can be forced into early blooming indoors by providing 12 weeks of chilling at temperatures between 1.6 to 7°C. Most bulbs can are planted in autumn or spring. Bulbs that bloom in early spring, like crocuses and snowdrops, should be planted in autumn so they have time to develop a good root system before winter sets in. Bulbs that bloom in late spring and summer, like gladioli and dahlias, should be planted in early to mid-spring.

How do bulbs that are grown from seeds get beneath the soil?

Did you ever wonder how plant bulbs get beneath the ground? Normal roots are produced during seed germination of bulbous plants, followed by the development of contractile roots. These specialised roots swell and shrink, gradually pulling the growing bulb underground. Some bulbs, such as those of the lily family, have a short, thickened rhizome that aids in this process. Others, like bulbs of the daffodil family, produce small tubers on their underground stems. These tubers act like little cushions, absorbing the energy from contractile roots and allowing the bulbs to be slowly pulled underground without damage.

Can you grow bulbs in pots?

All types of bulbs do well in pots. Mass-planted flowering bulbs and corms in pots make a stunning spring display. One popular technique is layering, by planting bulbs at different layers in the pot, with the largest at the bottom, and working your way up to the smallest close to the top.

Bulbs may or may not need to be removed from the pot once the season is over. Hardy bulbs must have a period of cold to break dormancy, therefore, bulbs that grow in climates with mild winters will need to be removed from pots and pre-chilled prior to planting out the next season. I have had success leaving daffodils in the ground in our warm Sydney climate, but other bulbs such as tulips and crocus have not flowered beyond one season as they were left in the ground and didn’t experience a cold enough winter.

On a personal level, I prefer to remove bulbs from pots once the leaves have died back, and reuse the pots for other flowers or plants.

How deep should bulbs be planted?

As a rule, true bulbs and corms should be planted two to three times the height or width of the bulb (whichever is greater). Rhizomes are planted at a depth of 3 cm (1 inch). Tubers should be planted at a depth of 10 cm (4 inches).


  1. Suzanne. (2021, March 2). The Science of Snowdrops. The Official Blog of Edvotek®.

Is Holly Toxic to Dogs?

Is holly toxic to dogs?

Holly is toxic to dogs. The toxic principle is saponins which can cause gastrointestinal disturbances (vomiting, diarrhea) when ingested.

Read more

How To Propagate String of Pearls

How to propagate string of pearls

String of pearls (Curio rowleyanus) is a hardy succulent native to South Africa which has seen a huge surge in popularity in the past few years. Its long stems contain pearl-shaped leaves that cascade down pots when they are long enough.

There are three ways to propagate string of pearls, direct, water, or layering. Each is as simple as the next. The key to propagation is to choose healthy parent stock.

Read more

Is Lavender Toxic to Dogs?

Is lavender toxic to dogs?

Lavender is toxic to dogs. The toxic principles are linalool and linalyl acetate which are biologically active compounds that can cause dermatitis or gastrointestinal upset depending on the route of exposure.

What is lavender?

  • Family: Lamiaceae
  • Botanical name: Lavandula spp.
  • Common names: Lavender
  • Leaf colour: Green/grey
  • Flower colour: Purple, pink, white
  • Toxicity: Toxic to dogs
  • Toxic properties: Linalool and linalyl acetate
  • Toxic parts: All parts

What is lavender?

Lavender is a hardy plant native to the Mediterranean and northern Africa and is a popular plant among gardeners for its ease of care and attractive, aromatic flowers. This herbaceous perennial is grown commercially for its essential oils¹. Lavender oil is widely used in herbal medicine as well as a fragrance in soaps, beauty products, scented candles and mist diffusers. The flowers of English lavender (Lavandula angustifolia) can be used to flavour drinks (teas, syrups, cocktails), salads, cakes, buttercream frosting and ice cream.

The highly scented volatile compounds are widely used in the fragrance and cosmetic industry and in alternative medicine. Lavender is cultivated worldwide for its volatile oil which has a number of actions including²:

  • Antimicrobial
  • Antispasmodic
  • Relieves anxiety
  • Antidepressant
  • Neuroprotective

In traditional human medicine, lavender oil has been used to relieve anxiety, insomnia, depression, headache, wound healing, muscle relaxation, post-surgical pain relief, hair loss, acne and eczema³.


Lavender contains 300 chemical compounds, two of which are linalool and linalyl acetate. These monoterpenes can cause dermal irritation as well as gastrointestinal disturbances (nausea, and vomiting).

Exposure occurs via dermal (skin) contact, ingestion and inhalation.

Most cases of lavender poisoning occur when the dog is exposed to undiluted lavender essential oil. There is some evidence that lavender essential oil applied to the collars of trial dogs may reduce stress⁴. However, pet owners must be aware there are risks when using essential oils on or around pets and should only use them after consultation with a veterinarian.

Clinical signs

Signs of lavender toxicity depend on the route of exposure. Smelling, brushing against, or consuming a small amount of lavender plant is unlikely to cause a toxic response in dogs, unless a large volume is consumed (unlikely). Swiss physician and chemist Paracelsus coined the term ‘the dose makes the poison‘. There is a significantly higher risk of poisoning from exposure to highly concentrated lavender essential oil than from the consumption of small amounts of plant matter. Exposure can be more dangerous if lavender essential oil or lavender-scented products are applied to the skin, which the dog may lick off.


  • Redness
  • Itching
  • Rash


  • Nausea
  • Drooling
  • Vomiting
  • Loss of appetite
  • Mouth ulcers
  • Oral irritation


  • Coughing
  • Sneezing
  • Wheezing
  • Difficulty breathing

First aid

If the dog has chewed part of a lavender plant, try to carefully remove any remaining plant matter. Then offer the dog a drink of something tasty such as milk. Contact your veterinarian if the dog develops clinical signs such as nausea and vomiting.

If the dog has had dermal (skin) exposure to lavender essential oil or products containing lavender, bathe the dog in warm water and plain dishwashing detergents such as Dawn, Morning Fresh or Fairy Liquid. This is the type of dishwashing liquid you use to hand wash.

Any dog who is experiencing breathing difficulty should see a veterinarian immediately. Have somebody ventilate the house by opening doors and/or windows to help dissipate any remaining lavender vapour.


The veterinarian will assess the dog and tailor the treatment according to the route of exposure and clinical signs.

  • For dogs whose skin or fur has been exposed, the veterinarian will bathe the dog in warm water and dishwashing detergent to remove any remaining lavender oil.
  • If ingestion was recent, the veterinarian can induce vomiting to remove any remaining plant matter (or product) from the gastrointestinal tract. This is usually followed by the administration of activated charcoal to bind to any remaining lavender and prevent further absorption.
  • Dehydration from fluid lost during vomiting can be managed with intravenous fluids. This can also promote urination, which will help to flush any remaining toxins from the body.
  • Antiemetics (anti-nausea) can be given to dogs with persistent vomiting, followed by a bland diet for several days to rest the gastrointestinal tract.
  • If the biochemical profile shows liver derangements, liver protectants such as S-Adenosylmethionine (SAMe) and silymarin, an extract of milk thistle can be administered. They act both as antioxidants and free radical scavengers.


Lavender plants are safe to grow in homes with dogs unless your dog has a serious interest in chewing the plant.

Do not use essential oils on dogs unless you have been instructed to do so by a veterinarian. There is some evidence that lavender essential oil is a mosquito repellent⁵, however, there is only limited data on the effectiveness of lavender plants. If you do burn or use an air mister in the home, ensure the room is well-ventilated and the dog has the opportunity to leave the room if the smell becomes overwhelming. Take special care around young kittens, lactating queens, and dogs with kidney or liver disease.


Is Thanksgiving Cactus Toxic to Dogs?

Is Thanksgiving cactus toxic to dogs?

Thanksgiving cactus is non-toxic to dogs. These popular Thanksgiving and holiday plants are safe to keep in homes with pets, but precautions must be taken when using fertilisers or pesticides on plants in homes with dogs as many are toxic.

What is Thanksgiving cactus?

Read more

Is Angel’s Trumpet (Brugmansia) Toxic to Dogs?

Is angel's trumpet toxic to dogs?

Angel’s trumpet (Brugmansia spp.) is highly toxic to dogs. The toxic principles are tropane alkaloids including atropine, hyoscyamine and scopolamine. Tropane alkaloids are secondary metabolites mostly found in the Solanaceae family which have powerful powerful anticholinergic agents.

Read more

Is Hippeastrum Toxic to Dogs?

Is Hippeastrum toxic to dogs?

Hippeastrum is toxic to dogs, the toxic principles are phenanthridine alkaloids including lycorine and tazzetine which have emetic properties. Exposure to small amounts can cause nausea, vomiting, hypersalivation, and diarrhea while large ingestions may cause tremors, depression and cardiac arrhythmias.

Read more

Soil Solarisation: The Eco-Friendly Way to Prep Your Garden

Soil solarisation

Solarisation is a broad-spectrum, chemical-free technique used to kill weeds, weed seeds and pathogens (fungi, bacteria, plant parasite nematodes, mites) utilising solar energy and clear plastic sheeting to trap heat in the upper soil layers. Studies have found several fungal pathogens have been almost completely eradicated using solarisation including Fusarium spp., Phytophthora spp., Pythium spp., Sclerotium spp.

Read more

Tomato Blight (Phytophthora infestans)

What is tomato blight?

What is tomato blight?  Ι   Transmission   Ι  Reproduction   Ι  What does tomato blight look like?   Ι  Treatment  Ι   Killing tomato blight in pots and soil   Ι  Difference between early and late blight  Ι   Prevention

What is tomato blight?

Also known as late blight, tomato blight is a highly contagious and destructive disease caused by Phytophthora infestans, a fungus-like organism (Oomycete) within the Kingdom of protists. Affected plants include potatoes, tomatoes and to a lesser extent eggplant and petunias.  Tomato blight was responsible for the Irish Potato Famine in the 1800s which killed 1 million people and is one of the most significant plant diseases, with a worldwide economic cost of US $5 billion annually.

There are three types of blight in tomatoes. Septoria leaf spot, early blight and late blight. This article refers specifically to late blight.

Read more