Kniphofia

[mikhurram]

Kniphofia or Red Hot Poker Lilies are regal drought tolerant plants which can be grown successfully in Lahore, Islamabad and northern regions upwards. They can tolerate any kind of soil conditions i.e. neutral, acidic or alkaline Ph levels as long as the medium has good drainage.

Generally Kniphofia flowers are bi-colour, starting out one shade and fading to a softer, different hue as the flower heads mature. The colour range is diverse ranging from yellow to green palette.

I began experimenting with Kniphofia 3 years ago and the first attempts were a failure. My initial medium was Bhal Patta mixed with perlite. The rhizomes though survived but never thrived and bloomed. Subsequently they were shifted to a raised soil bed with good drainage but didn’t thrive there also and the rhizomes started rotting.

A friend based in Lahore experimented with Kniphofia’s by placing them in raised bed filled with Bhal only and within a year the Kniphofia started blooming & multiplying. (refer to the last image).

Subsequently I found out that the reason for rotting was that Kniphofia’s suffer from a fungal disease called violet root rot which can spread rapidly through the border and they are also susceptible to slugs.

In a nutshell the following is a fairly comprehensive guide for growing Kniphofia’s
“ Requiring a well drained rich soil Kniphofia’s require ample moisture in its active growing period. Water quantity needs to be reduced after the flowers bloom and during wintertime the soil should be dry. It is very important to keep the soil dry, especially during winter as the plants are very susceptible to root rot. Fungicides are often used to save plants from root rot. Dry air is most suitable for the plant and it is best grown in garden soil which is very well-drained. In regions with high humidity and heavier clay soils, it is recommended to plant kniphofia in raised beds.

This year having some fresh stock of Kniphofia rhizomes , I intend to grow them in 12 inch pots filled with 70% Coarse Sand (Lawrencepur Sand) and 30% compost and 1 teaspoon of super-phosphate would be placed at the bottom of the pot. This soil mix in my opinion ought to be suitable for bearded iris also. I am grateful to Arif Sahib to some of his suggestions/tips during our course of discussion. I look forward to seeing suggestions/comments about the intended soil medium.

[mikhurram]

In addition to using the 70% Coarse Sand and 30% Compost mix, a mixture containing 35% of Karachi Bhalo Sand, 35% Lawrencepur Coarse Sand and 30% Compost was also used.

[newton]

Have you tried the pot in pot or pot in ditch method as that always ensures the best drainage, naturally eliminating excess water through the osmosis process.. Its difficult to describe but I will try to explain if your interested how and why it works

[mikhurram]

Sir, is the pot in pot method being referred by you the same being cited by the following url ?

http://www.floridafriendlyplants.com/Bl ... n-Pot.aspx

If so then a problem i foresee by using this method is that it can constrict the spread of the roots by making them pot bound thus may have an impact on the growth/health of the plant.

[newton]

It is one of two or three methods but not for the reasons cited by them

In Pakistan most of the soils around are fine loam, great when managed properly but in pots they retain an enormous amount of water and when dried out end up like concrete, secondly the temperature in these pots will be extremely high due to direct sunlight or radiated heat or both.

The key to good drainage is size and uniformity of soil particles. Large particles mixed with small particles will not improve drainage because the smaller particles fit between the large, increasing surface area which increases the capillary attraction and thus the water holding potential. It creates a perched water table. Since water and air cannot occupy the same space at the same time the plant roots drown and don't grow in that space.

Contrary to what some hold to be true, sand does not improve drainage. Pumice (aka lava rock), or pine barks are better additives which help promote drainage and porosity because of their irregular shape.

A better simpler thing like a wick placed from halfway in the pot and allowed to fall out several inches from the bottom drainage hole will pull out an enormous amount of water. It is merely changing the position of water being retained or perched within the soil, a bit like the litmus paper tests where water gets pulled up out of a beaker by capillary action but In this case downwards. To confirm the existence of the perched water table and the effectiveness of using a wick to remove it, try this experiment: Fill a soft drink cup nearly full of garden soil. Add enough water to fill to the top, being sure all soil is saturated. Punch a drain hole in the bottom of the cup and allow to drain. When the drainage stops, insert a wick several inches up into the drain hole . Take note of how much additional water drains. This is water that occupied the PWT before being drained by the wick. A greatly simplified explanation of what occurs is: The wick "fools" the water into thinking the pot is deeper, so water begins to move downward seeking the "new" bottom of the pot, pulling the rest of the perched water table along with it

Secondly most plants roots begin to suffer when actual root temperatures get to around 90º F and shut down around 95º F. Pot-in-pot growing can lower root temperatures significantly - by more than 15º F.
Farhan sahib (I believe) utilises a similar process for his rooftop gardening where he actually places a layer of soil under his pots to act as insulation from the heated concrete, however he is fulfilling a secondary point, not only does it insulate the pots it also improves drainage acting like a wick or the pot in pot method. If you want to grow more valuable, sensitive plants then for the latter reason alone I can see the pot in pot benefits.

In respect of the plants becoming pot bound, yes that is a valid point and a logical assumption but wouldn't it happen anyway if you didn't repot.

Heres wishing you the best of success with your plants next year, I must say you had some magnificent specimens last year.

[mikhurram]

An update on Kniphofia's. Bare root rhizomes were planted 2 weeks before and have starting sprouting new foliage. So far they are responding well to the soil mix consisting 70% [ in which equal proportions of Coarse Sand (Lawrencepur) and Bhalo Sand (Karachi Sand) were mixed ] and rest of 30% is Compost. Drainage is excellent.

[aykhan]

I have actually seen excellent drainage with addition of just regular sand. I don't know yet how it's going to take the heat. mikhurram where in Lahore did you get the Lawrencepur coarse sand and the Karachi Bhallu sand?

[mikhurram]

Usually coarse sand with compost is recommended for bearded irises also by experts.Lawrencepur sand through someone who had procured and bhallu sand from a friend. I heard from a friend that there is a sand dealer by the name of Baba Shera near Ravi who can arrange lawtencepur sand. Taxila sand considered the 2nd coarsest sand after lawrencepur is readily available in Lahore.

[aykhan]

Can you get me a contact number for the said gentleman near Ravi?

[mikhurram]

Have no contact number. You can send someone to Ravi who should be able dig out the address.