How to grow Potentilla
This large genus of plants can be split into two distinct types – shrubby and perennial. Both are grown for their attractive, nectar-rich, saucer to cup-shaped flowers which are produced over many months, often from spring right through until autumn. Usually derived from Potentilla fruticosa, shrubby types have twiggy, arching branches, finely divided leaves, and are a good choice for borders, or low, informal hedging (note they are deciduous, so will look bare and slightly unkempt over winter). Perennial types are clump-forming, and make easy, dependable additions to borders and containers. Those available to gardeners tend to be hybrids of P. nepalensis and P. atrosanguinea, valued for their single, semi-double, or double flowers throughout summer (often in red or yellow). The leaves of perennial species tell of their close relation to strawberries, so much so that where both are grown in close vicinity it can be difficult to tell them apart.
As well as the garden plants mentioned above, there are several UK native wildflower species. Common names include cinquefoil, tormentil, and silverweed.
Zantedeschia is a genus of flowering plants from the family Araceae and is native to southern Africa. With a rich history dating back to the Ancient Romans, these deciduous or semi-evergreen perennials have been used as a symbol of celebration. Zantedeschia was Named after Professor Giovanni Zantedeschia, an Italian botanist.
There are two main forms of Zantedeschia: hardy and tender. Hardy forms of the plant can be grown outdoors, enjoy moist soil and full sun or partially shaded conditions - these are known as Arum lilies. Tender forms of Zantedeschia prefer being grown in containers or pots and should be brought inside over the winter - these are known as Calla lilies.
With tuberous flora in all colours from whites, yellows and oranges to deep reds and purples, Zantedeschias are not to be overlooked in any garden, as long as they have sufficient sunlight to grow in.
Ready to learn more about growing Zantedeschia? Read on for all there is to know...
Key Information
Soil pH
Position
Hardiness
Where & when to plant Potentilla
Key Information
Position - Full sun
Soil - Thrives in almost any soil except for the extremes of waterlogged or bone dry. The exceptions to this are P. palustris (marsh cinquefoil) which is suitable for pond margins and bog gardens, and a few specialist rock garden species which prefer gritty, sharply drained soil.
Flowering Period - Summer
Hardiness - Hardy, usually rated H6 (-15 to -20°C) or H7 (-20°C and below).
Potentilla is best planted in autumn or spring. An autumn planting can be done by those gardening in mild conditions (and broadly speaking, this is the southern half of the UK). For those liable to cold, wet winters, it is best to wait until spring (generally the northern half of the UK, or those with very heavy soil). Planting can also be carried out in summer, though be prepared to water regularly.
Potentilla can thrive in a range of soils and stands up to air pollution and salty wind. Shrubby types are good for massing along slopes and banks to control erosion, and perennial types can effortlessly plug almost any sunny planting gap.
How to plant Potentilla
· For planting in the garden, dig the soil area removing any large stones and weeds and breaking up any lumps. Rake level and firm with your heels. Rake level again.
· Water plants well and allow to drain before planting.
· Dig a hole twice the width of the root-ball.
· Place the plant in the hole, ensuring the top of the root ball sits level with the surface of the soil. Too low and the plant may rot, too high and the roots can dry out.
· Backfill with soil and firm in gently with your foot.
· Soak well with water.
· Mulch around the base with organic matter, such as manure or garden compost.
· For planting in a container, first choose an appropriately sized pot. You may wish to grow your potentilla on its own (in which case use one just a few centimetres larger than the nursery pot) or as part of a mixed container. Always ensure there are plenty of drainage holes in the bottom.
· Use a good quality compost with a little horticultural grit mixed in and, if not already present (check the labelling on the bag) some slow-release fertiliser granules.
· Start by partially filling the pot with compost; enough so that when placed on it the upper surface of the root balls is about 3 centimetres lower than the top of the pot.
· Fill around the plant with compost, firming down with your fingers then adding a little more so it is held tight.
· Pick up the container and lightly tap on the potting bench or ground a few times to help further settle the compost around the plant.
· Soak well with water.
· A mulch with horticultural grit will look attractive and help to prevent a ‘cap’ or crust forming on the top of the compost (something container plants can suffer due to the artificial nature of their watering).
What to plant with Potentilla
Shrubby types have a size and scale which makes them appear equally at home amongst both herbaceous planting and other shrubs. We grow several in a flowering shrub border – the ultimate low-input way of achieving structure and colour in a garden, year after year. Here, its companions include viburnum, syringa, fuchsia, philadelphus, daphne, buddleja, and corylopsis.
For an herbaceous border that is almost as low-maintenance, mingle perennial types with other long-flowering, fuss-free classics such as gaura (now known as oenothera), geranium, erigeron, penstemon, nepeta, and erysimum.
How to care for Potentilla
Pruning and Deadheading
To keep shrubby species looking neat, they can be trimmed lightly each year in early spring before flower buds develop. Try to avoid doing so any later as it will mean losing out on flowers. Mature shrubs can also be thinned out to rejuvenate and encourage new growth. Remove a quarter to a third of the oldest, thickest stems at ground level.
Perennial species will benefit from a total cut back in autumn or winter. Expect a return to growth the following spring.
There is no need to deadhead shrubby species – the flowers are too small and numerous to make this feasible. On perennial species, however, removing the spent flower stems will prolong blooming and keep thing looking tidy.
Watering
Like all woody plants, shrubby potentilla establishes best when regularly watered during its first growing season in the ground. After this it should be largely self-sufficient. The perennial types can be soaked a handful of times during the first few weeks after planting, then largely left to their own devices in all but the hottest, driest weather.
Container-grown plants have less access to moisture so will need to be kept watered throughout every growing season. A useful rule of thumb to avoid overdoing it is to only water once the top couple of centimetres of compost have dried out. Be aware, however, that during the height of summer this can happen in as little as 24 hours. From mid-autumn, the British climate tends to take over watering needs, though do remember to step in in the event of an unseasonably dry spell.
Feeding
On healthy, fertile soil, an annual mulch of well-rotted organic matter (i.e., a layer of manure or garden compost applied to the soil around the plant) should provide adequate nutrients for your potentilla. This has the added benefit of suppressing weeds and locking in moisture, and is best done in autumn or spring.
For container-grown specimens, try to use a good quality compost with slow-release granules mixed in. This generally provides enough nutrients for six weeks, after which a monthly dose of balanced liquid feed will help maintain a healthy, thriving plant. It is also a good idea to get into the routine of repotting into fresh compost every couple of years, going up slightly in pot size each time. When this is no longer feasible, an annual topdress is advisable. Scrape away the top 5 centimetres of compost and replace with fresh (always containing slow-release feed!).
Cold Protection
Grown in well-draining conditions, potentilla is hardy enough to withstand a UK winter without the need for additional protection. Excessive winter wet is the enemy, making it important to avoid planting anywhere prone to waterlogging.
Pests and Diseases
Potentilla is considered trouble free.
How to propagate Potentilla
Potentilla is best propagated by softwood cuttings in early summer:
· Look for current year’s growth which is firm and woody at the base, while still soft and pliable at the tip. You’re aiming for a cutting of 10 centimetres or less (any longer and they are more likely to dry out and fail). For best results, choose stems where the leaf nodes are close together rather than far apart.
· Using a sharp knife or secateurs, sever the cutting from the plant and put in a plastic bag straight away.
· Fill a pot (or several, if you have a lot of cuttings) with a perlite-heavy compost mix (at least 50% perlite).
· Trim the end of the cutting to just below a node (point at which leaves grow).
· Remove lowest leaves and soft tip, leaving 2-4 leaves.
· If the remaining leaves are large, cut them in half with a sharp knife to reduce water lost through transpiration.
· Insert the cuttings into the compost and water lightly. Several cuttings can be put in the same container if there is enough space to do this without them touching.
· Place in a greenhouse or propagating unit if you have one, or covered with a plastic bag on a windowsill if not (out of direct sunlight).
· Keep the cuttings misted and occasionally watered until they root. You will know this has happened when roots emerge out of the bottom of the container.
· Gently remove rooted cuttings and pot them into individual pots. Grow on in a cool yet frost-free environment such as an unheated conservatory, greenhouse, or cold frame, until they are large enough to be potted or planted as above.
Perennial potentilla can be propagated by lifting and dividing established clumps in autumn or spring. As well as providing new plants, this breathes new life into tiring, congested clumps, and is recommended as a routine maintenance practice every 3-4 years.
· Choose a day when the soil is not frozen or waterlogged.
· Dig the plant out of the ground and shake off any excess soil.
· Separate into sections using either swift, cutting blows with a sharp spade, or two forks inserted back-to-back with tines touching, handles then pushed together to prise the plant apart.
· Discard old, damaged, or surplus pieces, keeping healthy, vigorous material with roots attached.
· Replant decent-sized pieces where desired, and any smaller bits can be potted up.
· Water well until fully established.
* Many plants carry Plant Breeders Rights and cannot be propagated for commercial purposes.
Common Potentilla Questions
Do you cut potentilla back?
Perennial types – yes.
Shrubby types should be left intact, despite what their bare, twiggy appearance may suggest! Trim these lightly in spring, as per our advice above.
How tall does potentilla get?
Shrubby species typically reach somewhere around the 1 metre mark, while perennial species tend to be low growing, i.e., 50 centimetres or less.
