Planted in the right location, lilac is a very vigorous shrub that increases in height and width by between 30 and 50 centimeters per year. Of course, this growth depends on the variety, because dwarf lilacs, which only grow up to 150 centimeters high, are significantly slower at an average of five to 20 centimeters a year. However, if the lilac does not really want to grow, there can be various reasons.
Nutrient deficiencies can be a reason for lack of growth
Common causes of lack of growth
A lilac that doesn't want to grow often doesn't bloom or only blooms a little. Both behaviors are a clear indication that the otherwise undemanding shrub does not like something. In most cases, the problem is location-related - it's too dark, the soil is too heavy, not permeable, or lacking in nutrients. Sometimes, however, an infection with a pathogen can also be the cause. Lilacs are particularly susceptible to fungi.
Wrong location
Sun, sun and even more sun - Syringa, as the lilac is called botanically, needs a full sun location where it is in direct light for at least four hours a day. If it is too dark for it (e.g. because a larger tree casts shadows at certain times of the day), it will not grow despite otherwise looking healthy and will often stop flowering. The only thing that helps is moving to a sunnier spot.
Unsuitable soil / waterlogging
The lilac does not like heavy, loamy soil either: here it cannot spread its roots, which run several meters under the soil, unhindered, and these soils often lack nutrients. However, the moisture accumulates here, which in turn can result in site-related waterlogging - with the result that the roots of the lilac rot. Here, too, the only thing that helps is moving to a more suitable soil or thorough soil improvement.
nutrient deficiency
A nutrient deficiency often occurs in very sandy or heavy soils, which should therefore be improved at the time of planting. As an immediate help, you can provide the lilac with an organic fertilizer, especially compost is very suitable. If you mulch the root disc, you may also have a nitrogen deficiency.
weakened by diseases
If the puny lilac has brown leaves or leaf spots, there is probably a disease caused by a bacterium or fungus. A pruning and strengthening of the bush with field horsetail, which is applied as a brew, helps here.
tips
Sometimes the root pressure of neighboring plants or the lawn in which the lilac is growing also causes reduced growth. In this case, the lilac simply does not have enough space.