Grey-brown spots on Lavendar?
Question:Hello, I have a French Lavendar tree in my front garden and the leaves have got grey-brown dots on them now. In the middle of the plant the leaves are dead. Is it normal for that season or is it some sort of pest?
Answers:
Lavender is traditionally a mediterranean plant, which is quite happy in British conditions provided a few basic rules are followed.
Soil
All Lavender needs well drained soil. On heavy soils it is best to incorporate gravel or small stones into the soil around and under the plant to improve drainage. Planting on a slight mound can also help. Lavender likes poorer thin soil than rich soils, so do not be tempted to mix in large amounts of organic matter. If planting in a container or pot ensure there are adequate drain holes in the bottom. and filling the bottom quarter with small stones will also help.
Position
A south facing sunny position is Lavender’s favourite place. The bracts on the top of stoechas are delicate and are best sheltered from persistent wind. Many stoechas are more sensitive to frost and so make ideal container plants that can be placed in a conservatory during the worst of the winter weather. However, with the milder winters that we are now experiencing it is now possible for some of the stoechas varieties to be planted outside all year round.
Spacing
For hedges 18 inches apart for most of the varieties. For Intermedia and larger types 22 inches. Smaller types such as Pink and Stoechas 16 inches. Groups of 3 planted together in a border will grow to form a mass of colour
Planting
Dig the hole slightly deeper than necessary, pour in 1 bucket of water and allow it soak away before planting. Moisten the compost before removing the pot. Plant just deep enough to allow a thin covering of soil over the top of the compost to retain moisture. Firm gently ensuring there is no depression next to the plant for water to accumilate in.
Watering
This should be unnecessary after planting except in very dry conditions, when for a few weeks an occasional light watering may be required. Plants in containers will need to be watered throughout the summer months.
Pruning
It is important to prune Lavender in the autumn to ensure vigorous growth the following year. As the colours start to fade in late august / early September prune back to within a hand’s distance of woody material. This may appear brutal but in fact is vital to the plant’s survival without it going ‘woody’. Stoechas varieties require ‘dead-heading’ throughout the year to keep the plant healthy along with its autumn trim.
The most common disease problem with lavender is wilt. Vascular wilts are very destructive diseases with typical symptoms characterized by rapid wilting, browning, and dying of leaves and succulent shoots of plants followed by the death of the plant. English lavender varieties are more susceptible to vascular wilts than lavendin varieties. Dark-flowered cultivars are less resistant to disease than the pale-flowered varieties. Cultivars with gray foliage are quite susceptible to infection. Vascular wilts are most common in the month of August when temperatures and humidity are high. If damaged plants are present, remove and destroy any infected plant material and avoid replanting with susceptible varieties. Dr. A. O. Tucker advises using one to two inches of white sand as a mulch around plants to reduce fungal pathogen infection. In addition, he found that the sand increased flower and oil production when compared to a control group of plants which were not mulched.
Try this website. I used to have lavender when I had a big yard and I know that you have replace the plants every 5 yrs. or so, or they become quite scraggly. You may have another problem. I'm not sure.
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